Journal articles: 'NBO analysis'

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Günay, N., H. Pir, D. Avcı, and Y. Atalay. "NLO and NBO Analysis of Sarcosine-Maleic Acid by Using HF and B3LYP Calculations." Journal of Chemistry 2013 (2013): 1–16. http://dx.doi.org/10.1155/2013/712130.

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We report a theoretical study on molecular structure, vibrational spectra, nonlinear optical (NLO), and natural bond orbital (NBO) analysis of sarcosine-maleic acid (C7H11NO6) in the ground state calculated by using the Hartree-Fock (HF) and density functional method (DFT/B3LYP) with 6–31++G(d,p) basis set. We repeat NBO calculations with 6–31G(d,p) basis set so as to see the diffuse function impact on NBO analysis. Stability of the molecule arising from hyper conjugative interactions and charge delocalization has been analyzed using NBO analysis. NBO analysis shows that there is a O–H⋯O and N–H⋯O hydrogen bond in the title compound, which is consistent with the conclusion obtained by the analysis of molecular structure. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Also, these results are supported by the NLO parameters. Finally, the calculated results were applied to simulate infrared and Raman spectra of the title compound which showed good agreement with experimental ones.

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Masingale, Michael P., Ericka F. Alves, Theresah N. Korbieh, Samar K. Bose, and Raymond C. Francis. "An oxidant to replace nitrobenzene in lignin analysis." BioResources 4, no. 3 (2009): 1139–46. http://dx.doi.org/10.15376/biores.4.3.1139-1146.

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Four metal organic frameworks (MOFs) are being evaluated as possible catalysts for alkaline lignin oxidation. One aspect of the screening process is the oxidation of in-situ hardwood lignin by a high mole ratio of Cu, Fe, or Cu + Fe contained in the MOFs. The MOF’s were prepared in a microwave-assisted synthesis. One of the MOFs, a benzenetricar-boxylic acid complex of Cu (II) and Fe (III), converted the phenylpropane (C9) units in in-situ poplar lignin to approximately 50% monomers. The ratio of syringyl (S) to guiacyl (G) monomers was similar to the S:G ratio obtained from nitrobenzene oxidation (NBO). The S:G ratio from NBO was then compared to that from MOF oxidation (MOFO) for two other poplars. The S:G ratios for the three poplars by MOFO were 1.20, 1.51 and 1.67, respectively while the corresponding NBO values were 1.25, 1.45 and 1.68. These initial results indicate that MOFO could be developed into a credible replacement for NBO, because it affords a higher yield of monomers when a large MOF dose is used. Some preliminary results are also presented for MOF acting as a catalyst (100 ppm Cu (II) plus 81 ppm Fe (III) in NaOH) for oxygenation of the hardwoods. The products from O2 + MOF are identical to MOF only, but the ratios amongst them are different.

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Fontes, F. A. O., K. K. P. Gomes, Francisca de Fatima P. Medeiros, C. P. Souza, J. F. Sousa, and Uilame Umbelino Gomes. "Synthesis of Niobium Carbide from Ammonium Niobium (V) Oxalate Precursor at Low Temperature in Rotating Cylinder Reactor." Materials Science Forum 498-499 (November 2005): 747–0. http://dx.doi.org/10.4028/www.scientific.net/msf.498-499.747.

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The reaction of oxalic precursor {(NH4)3[NbO(C2O4)3]H2O}, was prepared from the Nb2O5, to niobium carbide (NbC) were performed in a rotating cylinder reactor scale-lab designed to niobium carbide powders synthesis at low temperature (1173 K). The NbC was prepared by a oxalic precursor and as well of commercial niobium pentoxide under flowing CH4- H2 mixtures. The reactor was heated through a bi-partied electric furnace with programmable temperature. The reaction overall time was determined from the curve of methane absorption evolution by gas chromatograph (FID) analysis. The preliminary results showed that the conversion function depends on the rotation, temperature, mixture flow, CH4/H2 ratio and heating rate. The niobium carbide was characterized through X-ray diffraction and compared to the commercial products. The reaction of oxalic precursor {(NH4)3[NbO(C2O4)3]H2O} to niobium carbide (NbC) in 3% (v/v) CH4/H2 yielded smallest grain size as well smaller overall time when compared with obtained direct by commercial Nb2O5, however it had small mass conversion due the solid carryover not controlled.

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Joshi, Bhawani Datt, Poonam Tandon, and Sudha Jain. "Differential Scanning Calorimetry, NBO and Hyperpolarizability Analysis of Yohimbine Hydrochloride." Himalayan Physics 3 (December 26, 2012): 44–49. http://dx.doi.org/10.3126/hj.v3i0.7276.

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Yohimbine (C21H27N2O3) is one of the most important indole alkaloid. Differential scanning calorimetry, natural bond orbital (NBO) analysis and dipole moment with hyperpolarizability have been performed for molecular characterization. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using NBO analysis. The results show that charge in electron density (ED) in the ?* and ?* anti bonding orbitals and E(2) energies confirms the occurrence of intra molecular charge transfer (ICT) within the molecule.The Himalayan PhysicsVol. 3, No. 32012Page : 44-49

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Grabowski, Sławomir J. "Non-covalent interactions – QTAIM and NBO analysis." Journal of Molecular Modeling 19, no. 11 (2012): 4713–21. http://dx.doi.org/10.1007/s00894-012-1463-7.

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Glendening, Eric D., Clark R. Landis, and Frank Weinhold. "NBO 6.0: Natural bond orbital analysis program." Journal of Computational Chemistry 34, no. 16 (2013): 1429–37. http://dx.doi.org/10.1002/jcc.23266.

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Borrajo, Jacinto P., Sara Liste, Julia Serra, et al. "Evaluation of the Glass Bioactivity Grade by IR Analysis and the Stevels Parameter." Key Engineering Materials 284-286 (April 2005): 465–68. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.465.

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The structure of silica-based glasses consists on a disrupted network of SiO4 tetrahedra where network modifiers generate non-bridging oxygen groups (NBO), that play an important role at the initial steps of the bioactive process. Infrared spectroscopy is a sensitive technique to the presence of NBO groups and glass local structure modifications. The infrared study has been complemented with a theoretical approach using the Y Stevels parameter. Moreover, the in vitro bioactivity of the glasses as a function of Y Stevels paremeter has been studied, which can be a finding of a predictive tool for bioactivity of glasses.

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Tamai, Akari, Haruka Goto, Takuya Akiyama, and Yuji Matsumoto. "Revisiting alkaline nitrobenzene oxidation: quantitative evaluation of biphenyl structures in cedar wood lignin (Cryptomeria japonica) by a modified nitrobenzene oxidation method." Holzforschung 69, no. 8 (2015): 951–58. http://dx.doi.org/10.1515/hf-2014-0153.

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AbstractA modified alkaline nitrobenzene oxidation (NBO) method was developed to enable the analysis of the biphenyl structures of cedar wood lignin. The most essential point of the process is a modified work-up process in pyridine and a prolonged gas chromatography analysis of the silylated products. By applying this mean to cedar wood meal, a novel biphenyl product, dehydrovanillin-vanillic acid (1-carboxy-1′-formyl-4,4′-dihydroxy-3,3′-dimethoxy-5,5′-biphenyl), was detected together with known products, dehydrodivanillin and dehydrodivanillic acid. The highest total yield of biphenyl products was detected when NBO was carried out for 2–4 h at 170°C. The work-up procedure was slightly modified so that the biphenyl products can be quantified. The NBO conversion rates of biphenyl linkages of lignin were also examined with a biphenyl-type lignin model compound, and this gave rise to 75% biphenyl-type NBO degradation products. Under the same condition, the total yield of vanillin and vanillic acid (VA) from a non-condensed-type β-O-4 model compound was 89%. Because the latter did not exhibit any peak of the biphenyl products, it can be concluded that all the biphenyl products obtained by NBO (0.17 mmol g-1) were from the lignin of the native wood. It was calculated that at least 6.7 of 100 phenylpropanoid units of cedar lignin were involved in biphenyl structures even if the NBO conversion rate was not taken into consideration. The synthesis and analytical data of 11 lignin model compounds is described.

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Glendening, Eric D., Clark R. Landis, and Frank Weinhold. "Erratum: NBO 6.0: Natural bond orbital analysis program." Journal of Computational Chemistry 34, no. 24 (2013): 2134. http://dx.doi.org/10.1002/jcc.23366.

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Jiang, Nan, Ping Zhang, Wei-ran Hu, Zi-long Yao, and Bin Yu. "Similarities and Differences between Clavicular Bacterial Osteomyelitis and Nonbacterial Osteitis: Comparisons of 327 Reported Cases." Journal of Immunology Research 2021 (January 26, 2021): 1–11. http://dx.doi.org/10.1155/2021/4634505.

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Background. Currently, both clavicular bacterial osteomyelitis (BO) and nonbacterial osteitis (NBO) remain not well understood owing to their much lower incidences. This study is aimed at summarizing similarities and differences between clavicular BO and NBO based on comparisons of literature-reported cases. Methods. We searched the PubMed and Embase databases to identify English published literature between January 1st, 1980, and December 31st, 2018. Inclusion criteria were studies evaluating clinical features, diagnosis, and treatment of clavicular BO and NBO, with eligible data for synthesis analysis. Results. Altogether, 129 studies with 327 patients were included. Compared with BO, clavicular NBO favored females (P<0.001) and age below 20 years (P<0.001) and mostly presented in a chronic phase (disease term exceeding 2 months) (P<0.001). Although local pain and swelling were the top two symptoms for both disorders, fever, erythema, and a sinus tract were more frequently found in BO patients (P<0.01). Although they both favored the medial side, lesions in the clavicular lateral side mostly occurred in BO patients (P=0.002). However, no significant differences were identified regarding the serological levels of white blood cell count (P=0.06), erythrocyte sedimentation rate (P=0.27), or C-reactive protein (P=0.33) between BO and NBO patients before therapy. Overall, the BO patients achieved a statistically higher cure rate than that of the NBO patients (P=0.018). Conclusions. Females, age below 20 years, and a long duration of clavicular pain and swelling may imply NBO. While the occurrence of a sinus tract and lesions in the lateral side may be clues of BO, inflammatory biomarkers revealed limited values for differential diagnosis. BO patients could achieve a better efficacy than the NBO patients based on current evidence.

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Shekarkhand, Marzieh, Karim Zare, Majid Monajjemi, Elham Tazikeh-Lemeski, and Masoumeh Sayadian. "Computational study of heterocyclic anticancer compounds through nbo method." Nexo Revista Científica 35, no. 01 (2022): 367–81. http://dx.doi.org/10.5377/nexo.v35i01.13982.

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In the present study NBO method contain the HOMO and the LUMO energies are calculated for 10 different heterocycles anticancer drug using B3LYP/6-31G(d,p). Frontier molecular orbitals (HOMO and LUMO) and Molecular Electrostatic Potential map of the compound was produced by using the π stacking of structures and anticancer activity of molecules. The NBO analysis was suggested that the molecular system contains π- π interaction, strong conjugative interactions and the molecule become more polarized owing to the movement of π-electron cloud from donor to acceptor. NBO, HOMO and LUMO energies, were investigated and Anticancer activity of Aromatic Heterocyclic compounds was investigated by NBO study and result was compared with our previous study about NICS and S-NICS of these 10 anticancer drug. the HOMO/LUMO gap of the heterocycle anticancer drug is significantly different from each other. The NBO method is used in both symmetric and asymmetric molecules and provides accurate information on the aromatics of the compound, especially the heterocyclic rings. It also provides accurate information in protected areas. Molecule 8 has the highest amount of HOMO and therefore aromaticity among the studied compounds which confirms the result of molecular orbital examination.

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Lykhach, Yaroslava, Jan Plšek, Ilona Spirovová, and Zdeněk Bastl. "Thermal Stability of Au/NbOx/Nb and Au/Nb2O5/W Model Catalysts Studied by Angle-Resolved X-Ray Photoelectron Spectroscopy." Collection of Czechoslovak Chemical Communications 68, no. 10 (2003): 1791–804. http://dx.doi.org/10.1135/cccc20031791.

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The thermal stability of gold deposited on Nb2O5/W, Nb2O5/Nb and NbO/Nb substrates was investigated by angle-resolved X-ray photoelectron spectroscopy. Gold in amounts 0.1-1.2 monolayer was vapour-deposited on an oxide substrate under ultrahigh vacuum. A shift of the Au (4f) core level towards higher binding energies and an increase in the line width with decreasing surface coverage by Au were observed for all supports and explained by final state effects in the photoemission process. The lower magnitude of the shift observed in the case of Au/NbO/Nb was attributed to better screening of the core hole by electrons of the metallic NbO phase. The results present evidence that on heating of the Au/Nb2O5/W system up to 550 °C only agglomeration occurred without significant diffusion of Au into the oxide substrate. Annealing of the Au/Nb2O5/Nb model catalyst above 350 °C resulted in reduction of Nb2O5 to suboxides and inward diffusion of Au. Diffusion into the substrate above 350 °C has also been observed for the Au/NbO/Nb sample. The distribution of Au within the surface layers of substrate has been estimated by analysis of Au (4f) and Nb (3d) angle-resolved spectra. The inward diffusion of Au on annealing observed for the Nb2O5/Nb and NbO/Nb substrates is facilitated by a high density of defects in NbO. Besides information on the particular Au/Nb2O5/W, Au/Nb2O5/Nb and Au/NbO/Nb systems, our results demonstrated potentials of angle-resolved photoelectron spectroscopy for determination of the distribution of a metal in annealed model catalysts and for study of extended interfaces.

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Manelis, A., C. D. Ladouceur, S. Graur, et al. "Altered functioning of reward circuitry in youth offspring of parents with bipolar disorder." Psychological Medicine 46, no. 1 (2015): 197–208. http://dx.doi.org/10.1017/s003329171500166x.

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Background.Offspring of parents with bipolar disorder (BD) (BO) are at higher risk of BD than offspring of parents with non-BD psychopathology (NBO), although both groups are at higher risk than offspring of psychiatrically healthy parents (HC) for other affective and psychiatric disorders. Abnormal functioning in reward circuitry has been demonstrated previously in individuals with BD. We aimed to determine whether activation and functional connectivity in this circuitry during risky decision-making differentiated BO, NBO and HC.Method.BO (n = 29; mean age = 13.8 years; 14 female), NBO (n = 28; mean age = 13.9 years; 12 female) and HC (n = 23; mean age = 13.7 years; 11 female) were scanned while performing a number-guessing reward task. Of the participants, 11 BO and 12 NBO had current non-BD psychopathology; five BO and four NBO were taking psychotropic medications.Results.A 3 (group) × 2 (conditions: win-control/loss-control) analysis of variance revealed a main effect of group on right frontal pole activation: BO showed significantly greater activation than HC. There was a significant main effect of group on functional connectivity between the bilateral ventral striatum and the right ventrolateral prefrontal cortex (Z > 3.09, cluster-p < 0.05): BO showed significantly greater negative functional connectivity than other participants. These between-group differences remained after removing youth with psychiatric disorders and psychotropic medications from analyses.Conclusions.This is the first study to demonstrate that reward circuitry activation and functional connectivity distinguish BO from NBO and HC. The fact that the pattern of findings remained when comparing healthy BO v. healthy NBO v. HC suggests that these neuroimaging measures may represent trait-level neurobiological markers conferring either risk for, or protection against, BD in youth.

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Dittz, Erika Silva, Claudia Regina Lindgren Alves, Elysângela Dittz Duarte, and Lívia De Castro Magalhães. "Contribution of the Newborn Behavioral Observations (NBO) for the maternal care of preterm neonates." Journal of Human Growth and Development 27, no. 3 (2017): 262. http://dx.doi.org/10.7322/jhgd.125522.

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Introduction: In the care of preterm newborn, practices that favor the participation of mothers in care are recommended. The use of appropriate instruments by professionals can contribute to strengthen maternal participation.Objective: To analyse the contributions of the use of the Newborn Behavioral Observations (NBO) for the maternal care of preterm neonates.Methods: Descriptive qualitative study, using participant observation and semi-structured interviews with 14 mothers of preterm newborns who underwent NBO. Data was submitted to content analysis, assinted by the software MAXQda 12.Results: It was found that the mothers' prior perceptions of the newborn´s capacities or how they react to environmental stimuli do not differ from what was observed and reported by them after NBO. However, it was verified that NBO confirms this perception and broadens the mothers' understanding of the meaning of the newborn's behavior. Participating in the NBO helped the mothers to identify strategies to find the needs of the newborn, qualifying the care already performed by them and opening new possibilities for maternal care.Conclusions: The NBO is an instrument that favors the mother's learning about the behavior of the newborn and contributes to the construction of practices with potential to be used by them within daily care. This allows us to consider it as a tool that favors the mother-baby relationship, contributes to the mother's participation in the care, and supports the mother in the construction of her autonomy for the continuity of the newborn's care after hospital discharge.

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Joshi, Bhawani Datt, and Manoj Kumar Chaudhary. "NBO, nonlinear optical and thermodynamic properties of 10-Acetyl-10H-phenothiazine 5-oxide." BIBECHANA 15 (December 19, 2017): 131–39. http://dx.doi.org/10.3126/bibechana.v15i0.18385.

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In this paper, natural bond orbital (NBO) analysis, nonlinear optical and the thermodynamic properties of 10-Acetyl-10H-phenothiazine 5-oxide have been analyzed by employing density functional theory level employing 6-311++G(d,p) basis set. NBO analysis reveals that the intra- intermolecular charge transfer occurs within the molecule leading to the stabilization. The predicted nonlinear optical properties (NLO) like; polarizability and first hyperpolarizabiliy support that the molecule could attract the interests for future investigation.BIBECHANA 15 (2018) 131-139

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Volkova, Tatiana G., Iroda Mamirjon kizi Abdukhalimova, and Irina O. Talanova. "Hydrogen bonds in molecular crystals alanine and tyrosine: NBO analysis." Butlerov Communications 64, no. 10 (2020): 1–6. http://dx.doi.org/10.37952/roi-jbc-01/20-64-10-1.

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At present, the theoretical concepts of the hydrogen bond (H-bond) in condensed media, for example, in living systems, biomolecules, are not fully solved. Quantum chemical modeling is used as one of the methods for studying the nature and determining the strength of the H-bond. In this paper, we continue to study the system of hydrogen bonds in molecular crystals of alanine and tyrosine. The dimers of these amino acids were modeled using the DFT method using the B97D functional with bases 6-31++G**. In the framework of NBO analysis, the stabilization energies of the formed hydrogen bond and the value of the transferred charge are calculated. It is shown that in alanine dimers, the main factor affecting the h-bond stabilization energy is the geometric parameters and, first of all, (N-H...O). The binding σ-orbital of the hydrogen bond is the result of the interaction of a hybrid NBO of the lone electron pairs of an oxygen atom and a loosening σ*-NBO N−H bond. The nature of bond formation in all three cases is the same, and the charge transfer value is greater than the value of the bond criterion, which indicates the presence of hydrogen bonds in all analyzed alanine systems. In tyrosine dimers, two H-bonds are formed that are similar in nature, as well as in geometric and energy parameters. The third H-bond is very weak, and the amount of charge transfer indicates its absence. The main interaction between the molecules in the third tyrosine dimer is the H-bond between the –СОО− and –OH groups. It was found that the scheme of formation of hydrogen bonds in molecular crystals of tyrosine is somewhat different from that of alanine.

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Han, Lingli, Ling Nie, and Tao Liu. "The regioselectivity in the platinum-catalyzed domino reaction to access alkynylated indoles: a theoretical study." New Journal of Chemistry 41, no. 22 (2017): 13798–803. http://dx.doi.org/10.1039/c7nj03063k.

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Rozada, Thiago de Castro, Rodrigo Meneghetti Pontes, Roberto Rittner, and Ernani Abicht Basso. "Stereoelectronic effects of the glycosidic linkage on the conformational preference of d-sucrose." RSC Advances 6, no. 114 (2016): 112806–12. http://dx.doi.org/10.1039/c6ra24413k.

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Usman, Mohammad, Rais Ahmad Khan, Ali Alsalme, et al. "Structural, Spectroscopic, and Chemical Bonding Analysis of Zn(II) Complex [Zn(sal)](H2O): Combined Experimental and Theoretical (NBO, QTAIM, and ELF) Investigation." Crystals 10, no. 4 (2020): 259. http://dx.doi.org/10.3390/cryst10040259.

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The Zn(II) complex of salen-like scaffold [Zn(sal)](H2O) was synthesized and characterized by elemental analysis, IR, UV–Vis, and 1H-NMR spectroscopic techniques. The structure of complex was confirmed by single crystal X-ray diffraction studies. In the complex, Zn (II) was placed in the inner N2O2 compartment of the salen scaffold in square planar geometry and crystallized in the monoclinic space group P21/n. DFT and TDDFT calculations were performed to reproduce the experimentally observed structural and spectroscopic (IR and UV–vis) findings. The bonding of the Zn(II) framework in the [Zn(sal)](H2O) complex was explored in depth. The theoretical approaches employed were perturbation theory within the context of the natural bond orbital (NBO) framework, and quantum theory of atoms in molecule (QTAIM) and electron localization function (ELF) analysis. The study begins by delineating the difference between the NBO and QTAIM approaches. This paper thus exhibits the supportive nature of NBO theory and QTAIM in discussion of the bonding in the [Zn(sal)](H2O) complex, when both the methodologies are used in combination.

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Gunawan, Untung, Slamet Ibrahim, Atthar Luqman Ivansyah, and Sophi Damayanti. "Theoretical insight and molecular recognition of fluconazole molecularly imprinted polymers: a combined computational and experimental analysis." RSC Advances 15, no. 24 (2025): 19158–75. https://doi.org/10.1039/d5ra03211c.

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Analysis of fluconazole and 39 monomers for MIP design showed 2-acrylamido-1-ethanesulfonic acid as the optimal monomer in chloroform. QTAIM, NBO, and NCI-RDG analyses revealed the key hydrogen bond between H51 and N33 in the complex formation.

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Esteban, Angel L., Maria P. Galache, Francisco Mora, et al. "Vicinal NMR Proton−Proton Coupling Constants. An NBO Analysis." Journal of Physical Chemistry A 105, no. 21 (2001): 5298–303. http://dx.doi.org/10.1021/jp0100811.

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Weinhold, F., C. R. Landis, and E. D. Glendening. "What is NBO analysis and how is it useful?" International Reviews in Physical Chemistry 35, no. 3 (2016): 399–440. http://dx.doi.org/10.1080/0144235x.2016.1192262.

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Rajalakshmi, K., and S. Sharmila. "Spectroscopic Studies and Vibrational Assignments, Homo- Lumo, UV-VIS, NBO Analysis of Benzonitrile." International Journal of ChemTech Research 13, no. 3 (2020): 225–39. http://dx.doi.org/10.20902/ijctr.2019.130320.

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The Fourier transform infrared and FT-Raman spectra of Benzonitrile have been recorded in region of 4000-400 and 4000-100 cm -1 respectively. A complete assignments and analysis of fundamental vibrational modes of the molecule have been carried out. The observed fundamental modes have been compared with harmonic vibrational frequencies computed using ab initio and density functional theory calculations by employing B3LYP functional at 6-311G(d, p) level and HF/6-311G(d, p).UV-Vis spectrum of the compound has been recorded, the natural bond orbital (NBO) electronic properties, such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies have been calculated with B3LYP/6-311G(d, p) level. These calculated energies show that charge transfer occurs within molecule. NBO analysis, thermodynamics properties and Mulliken charges of the title molecule are also calculated and interpreted

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Jiao, Yinchun, and Frank Weinhold. "NBO/NRT Two-State Theory of Bond-Shift Spectral Excitation." Molecules 25, no. 18 (2020): 4052. http://dx.doi.org/10.3390/molecules25184052.

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We show that natural bond orbital (NBO) and natural resonance theory (NRT) analysis methods provide both optimized Lewis-structural bonding descriptors for ground-state electronic properties as well as suitable building blocks for idealized “diabatic” two-state models of the associated spectroscopic excitations. Specifically, in the framework of single-determinant Hartree-Fock or density functional methods for a resonance-stabilized molecule or supramolecular complex, we employ NBO/NRT descriptors of the ground-state determinant to develop a qualitative picture of the associated charge-transfer excitation that dominates the valence region of the electronic spectrum. We illustrate the procedure for the elementary bond shifts of SN2-type halide exchange reaction as well as the more complex bond shifts in a series of conjugated cyanine dyes. In each case, we show how NBO-based descriptors of resonance-type 3-center, 4-electron (3c/4e) interactions provide simple estimates of spectroscopic excitation energy, bond orders, and other vibronic details of the excited-state PES that anticipate important features of the full multi-configuration description. The deep 3c/4e connections to measurable spectral properties also provide evidence for NBO-based estimates of ground-state donor-acceptor stabilization energies (sometimes criticized as “too large” compared to alternative analysis methods) that are also found to be of proper magnitude to provide useful estimates of excitation energies and structure-dependent spectral shifts.

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Ramlath, K. T. "THEORETICAL AND EXPERIMENTAL FT-IR , OPTIMISED MOLECULAR GEOMETRY, HOMO–LUMO,MULLIKEN CHARGES AND NBO ANALYSIS OF SOME SUBSTITUTED TRIAZOLES." International Journal of Advances in Engineering & Scientific Research 1, no. 2 (2014): 56–79. https://doi.org/10.5281/zenodo.10720144.

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ABSTRACT                         Quantum chemical calculations have been widely used to monitor reaction mechanisms, to study inhibition of the corrosion of metals. DFT is considered as a very useful technique to probe as well as to analyze the experimental data. This study proposes a joint experimental and theoretical investigation of FTIR and vibrational characteristics of Triazoles (4-amino- 4H-1, 2, 4-triazole-3, 5-dimethanol(ATD ) and 3-amino-5-methylthio-1H-1,2,4-triazole(SAMT)) and also the theoretical determination of the optimized molecular geometries, HOMO–LUMO, Mulliken charges and NBO analysis using Density Functional Theory (DFT) method were conducted focusing on the corrosion inhibition efficiencies of ATD and SAMT.The room temperature Fourier transforms infrared spectra of the compounds-ATD and SAMT were measured using a JASCO FT/IR-4100 spectrometer. In this study, the geometry of the compounds ATD and SAMT   were optimized with  DFT/B3LYP method using 6-31G (d,p) basis set. The molecular structural parameters ,the complete vibrational analysis, NBO analysis, HOMO and LUMO analysis and Mulliken population analysis of the compounds ATD and SAMT  were performed on the basis of DFT calculations at the B3LYP/6-31G(d,p) basis set. The molecular structural parameters were compared with the available XRD data for ATD and showed excellent agreement. The FT-IR spectral measurement has been made both for the ATD and SAMT. The consistency between the calculated and experimental FT-IR data indicates that the B3LYP/6-31G(d,p) method can generates reliable geometry and related properties for the compounds. The difference between the observed and scaled wave number values of most of the fundamentals is very small. The corrosion inhibition efficiency of the inhibitors and the values, EHOMO, ELUMO, ELUMO - EHOMO and ΔN of inhibitors were calculated by DFT method are correlated. DFT method shows that ATD has better inhibitive efficiency than SAMT towards aluminium at lower inhibitor concentrations. Key words: DFT/B3LYP method, vibration analysis, NBO analysis, HOMO and LUMO analysis and Mulliken population analysis

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Zhang, Jiangle, Shanjun Chen, Yihuang Jiang, et al. "The photoelectron-imaging spectroscopic study and chemical bonding analysis of VO2−, NbO2− and TaO2−." RSC Advances 10, no. 68 (2020): 41612–17. http://dx.doi.org/10.1039/d0ra07583c.

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The transition-metal di-oxides, namely VO2−, NbO2− and TaO2− have been studied using photoelectron velocity map imaging (PE-VMI) in combination with theoretical calculations.

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Mitrasinovic, Petar M. "Acrylonitrile (AN)Cu9(100) interfaces: Electron distribution and nature of bonded interactions." Canadian Journal of Chemistry 81, no. 6 (2003): 542–54. http://dx.doi.org/10.1139/v03-043.

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There is a fundamental interest in the investigation of the interfacial interactions and charge migration processes between organic molecules and metallic surfaces from a theoretical standpoint. Quantum mechanical (QM) concepts of bonding are contrasted, and the vital importance of using combined QM methods to explore the nature of the interfacial interactions is established. At the one-electron level, the charge distribution and nature of bonded interactions at the ANCu9(100) (neutral and charged (1)) interfaces are investigated by both the Becke (B) Vosko (V) Wilk (W) Nusair (N)/DZVP density functional theory (DFT) method and the MP2/631+G* strategy within the conceptual framework provided by natural bond orbital (NBO) natural atomic orbital (NAO) population analysis and Atoms-In-Molecules (AIM) theory. By this approach, the interfacial interactions are given physical definitions free of any assumptions and are visualized by using the topological features of the total electron density. A natural link between the electron density on the one side and the shapes (not energies) of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) on the other side is clarified. The question of whether the spatial extents of the HOMO and LUMO resemble the corresponding spatial maps of the negative (charge locally concentrated) and positive (charge locally depleted) Laplacian of the total electron density in [ANCu9(100)]1 is addressed.Key words: ANCu9(100) interfaces, NBONAO population, electron distribution, AIM, bonded interactions.

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Маслобоева, Софья Михайловна. "ANALYSIS OF METHODS FOR SYNTHESIS OF A BORON-DOPED LITHIUM NIOBATE CHARGE USED FOR GROWING SINGLE CRYSTALS." Physical and Chemical Aspects of the Study of Clusters, Nanostructures and Nanomaterials, no. 13 (December 23, 2021): 750–59. http://dx.doi.org/10.26456/pcascnn/2021.13.750.

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Проведен анализ известных методов синтеза шихты ниобата лития, легированной бором, которая используется при выращивании монокристаллов высокого оптического качества методом Чохральского. Установлено, что способ гомогенного легирования (шихта получается из прекурсора NbO :B и LiCO) по сравнению с твердофазным (шихта получается из смеси LiCO: NbO : HBO ) позволяет выращивать кристаллы LiNbO: B с более однородным распределением в них примеси бора, а также в объеме расплава, при этом упрощаются технологические режимы, устанавливаемые при росте кристаллов. В работе впервые рассмотрен жидкофазный метод синтеза шихты, исключающий стадию прокалки гомогенизированной смеси пентаоксида ниобия и карбоната лития. Результаты имеют важное значение при выборе технологии выращивания легированных бором монокристаллов ниобата лития для конкретных областей техники. Known methods of a boron doped lithium niobate charge synthesis were analyzed. Such a charge is applied for the growth by Czochralski of single crystals with high optical quality. Homogeneous doping (the charge is obtained from precursor NbO:B and LiCO) was compared with solid phase doping (the charge is obtained from the mixture LiCO: NbO: HBO). Homogeneous doping was determined to help produce LiNbO: B crystals with a more uniform distribution of a boron dopant, boron distributes more uniform in the melt volume; technological regimes established during crystal growth become easier. For the first time the paper considers liquid-phase charge synthesis method; the method excludes the stage of annealing of homogenized mixture of niobium pentoxide and lithium carbonate. Results are crucial for the choice of technology at growing of boron doped lithium niobate crystals for exact areas of technics.

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Lee, E. H., and L. K. Mansur. "Ion-beam-induced formation of a stable phase at the expense of an otherwise dominant metastable phase." Journal of Materials Research 2, no. 3 (1987): 291–93. http://dx.doi.org/10.1557/jmr.1987.0291.

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Thermal aging and irradiation experiments were carried out in Fe–Ni–Cr base alloys containing Ti or Nb as well as low levels of oxygen, nitrogen, and carbon. After aging, fine dispersions of TiC and NbC were formed. However, after irradiation the Ti-containing alloy precipitated Ti(N,O) rather than TiC, while the Nb-containing alloy precipitated NbC. Analysis of the energetics of these reactions reveals that the Ti(N,O) phase is thermodynamically more stable than the TiC phase, while the NbC phase is more stable than the NbO phase. These results are therefore consistent with observed behavior. While it is well known that irradiation can drive a system away from equilibrium, the present results show that irradiation also can catalyze the formation of a more stable phase at the expense of a persistent metastable phase.

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Hu, Hanyu, Sami Soudani, Jonathan Hamon, Nicolas Trcera, Michael Paris, and Yann Morizet. "Multi-Spectroscopic Investigations for Comprehensive Structural Analysis of Aluminoborosilicate Glasses: I. Integrating Raman, XPS, XAS and NMR Techniques." Glass Europe 2 (December 20, 2024): 181–211. https://doi.org/10.52825/glass-europe.v2i.1422.

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For relatively simple glasses, such as binary or ternary glass systems, various characterization techniques have proven effective for determining network structures. However, structural analysis of multicomponent glass systems remains challenging due to complex network structures. In this study, we employed Raman, XPS, XAS, and NMR techniques to investigate the structure of soda lime aluminoborosilicate glasses. Our focus was on the polymerization degree of the silicate network (average Qn value), the content of Non-Bridging Oxygen (NBO%), the connectivity between borate species ([3]B-O-[3]B% and [3]B-O-[4]B%), and the chemical environment of Ca and Na cations. Raman spectral decomposition enabled the determination of the polymerization degree of the silicate network, which agreed well with the values calculated from 11B and 27Al NMR spectra for glasses without B-NBO species. XPS O1s spectra decomposition provided consistent NBO content values with those calculated from NMR results. The 11B DQ-SQ NMR spectra can analyse the connectivity changes between borate species across different glass compositions. The 23Na NMR spectra can provide a comprehensive view of the local environment of Na. The XAS spectra provided reliable insights into the local environment of Ca, detailing first shell configurations not easily obtained via NMR. We also presented an analysis scheme for 11B NMR spectra to distinguish between [4]B(3Si,1B) and [4]B(4Si,0B) species. This study emphasizes the necessity of using a multi-spectroscopic approach to analyse the complex glass network structure.

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Atalay, Abdurrahman, Fatih Çelik, Yasemin Ünver, Kemal Sancak, and Kamil Kaygusuz. "Molecular Conformational Analysis, Spectroscopic Characterization, Intramolecular Hydrogen Bonding and Natural Bond Analysis of (E,Z)-2-(4- Amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4-triazole-1-yl)-N'- (thiophene-2-ylmethylene) Acetohydrazide." Letters in Organic Chemistry 16, no. 3 (2019): 215–25. http://dx.doi.org/10.2174/1570178615666181002141949.

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The optimized structural parameters and electronic properties including frontier molecular orbital (FMO) analysis, molecular electrostatic potential and NBO charge analysis of (E,Z)-2-(4- amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4-triazole-1-yl)-N&#039;-(thiophene-2-ylmethylene) acetohydrazide were investigated by using density functional theory (DFT) at B3LYP/6-311++G(d,p) level. The global reactivity parameters were evaluated in accordance with the energy values of HOMO and LUMO of each determined conformer. The molecule was experimentally characterized by means of FT-IR and NMR spectroscopic methods and also theoretically by B3LYP/6-311++G(d,p) and B3LYP/cc-pVTZ method (FT-IR and NMR, respectively). The theoretical results of spectroscopic analysis show good agreement with experimental outcomes. The natural bond orbital (NBO) analyses for studied conformers were performed at B3LYP/6-311++G(d,p) level to find hyperconjugative interactions as well as intramolecular hydrogen bond interaction. Besides, theoretical results indicate that the optimized structure of conformer E and Z possesses N‒H···N and N‒H···S weak hydrogen bonding, respectively.

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32

Parthasarathi, R., V. Subramanian, and N. Sathyamurthy. "Electron Density Topography, NMR, and NBO Analysis of Water Clusters." Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry 38, no. 1 (2008): 18–27. http://dx.doi.org/10.1080/15533170701851250.

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Li, Xiao-Hong, Geng-Xin Yin, and Xian-Zhou Zhang. "Natural bond orbital (NBO) population analysis of some benzyl nitrites." Journal of Molecular Structure: THEOCHEM 957, no. 1-3 (2010): 61–65. http://dx.doi.org/10.1016/j.theochem.2010.07.005.

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Shainyan, Bagrat A., Nina N. Chipanina, Larisa P. Oznobikhina, and Vladimir I. Meshcheryakov. "Basicity of trifluoromethylsulfonylformamidines. DFT and FTIR study and NBO analysis." Journal of Physical Organic Chemistry 29, no. 2 (2015): 92–100. http://dx.doi.org/10.1002/poc.3503.

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Плиговка, А. Н., П. А. Юнин, А. В. Гога, С. А. Королев, Г. Г. Горох та Е. В. Скороходов. "Морфология и состав дефектированных массивов ниобиевых оксидных неоднородностей, сформированных анодированием двуслойной системы Al/Nb". Журнал технической физики 90, № 11 (2020): 1854. http://dx.doi.org/10.21883/jtf.2020.11.49974.149-20.

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The work is devoted to X-ray diffraction research of defected niobium oxide nonuniform (NON) arrays and niobium oxide nanocolumns formed by electrochemical anodizing. The results obtained allow to make an assumption about the probable presence of significant amount of NbO, NbO0.7, Nb2O5 and small amount of NbO2, and Al in the composition of defected NON and the presence of all these substances in the nanocolumns of niobium oxide except NbO0.7, but in smaller quantities. A comparative analysis of the NON structure and the nanocolumns makes it possible to isolate, probably, significant amount of Nb0.94O0.06, Nb6O in the defective nanocolumns, which was not found in NON.

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Gnanasekar, Sharon Priya, and Elangannan Arunan. "A Detailed Classification of Three-Centre Two-Electron Bonds." Australian Journal of Chemistry 73, no. 8 (2020): 767. http://dx.doi.org/10.1071/ch19557.

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We evaluate the three-centre two-electron (3c-2e) bonds using atoms in molecules (AIM) and natural bond orbital (NBO) theoretical analyses. They have been classified as ‘open (V)’ or ‘closed (Δ)’, depending on how the three centres were bonded. Herein, we show that they could be classified as V, L, Δ, Y, T and I (linear) arrangements depending on the way the three centres are bonded. These different structures are found in B2H6 (V), CH5+ (V), Me-C2H2+ (L), B3+ (Δ), C3H3+ (Δ), H3+ (Y), 2-norbornyl+ (T), SiH5+ (T), and Al2H7− (I). Our results suggest that CH3Li2+ does not contain a 3c-2e bond according to NBO analysis. Therefore, we propose that 3c-2e bonds are classified more accurately as V, L, Δ, Y, T, or I, based on the electron density topology.

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Diwaker and Abhishek Kumar Gupta. "Quantum Chemical and Spectroscopic Investigations of (Ethyl 4 hydroxy-3-((E)-(pyren-1-ylimino)methyl)benzoate) by DFT Method." International Journal of Spectroscopy 2014 (July 9, 2014): 1–15. http://dx.doi.org/10.1155/2014/841593.

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In the present work we have reported the optimized ground state geometry, harmonic vibrational frequencies, NMR chemical shifts, NBO analysis, and molecular electrostatic potential surface map of the title compound using DFT/B3LYP/6-311++G(2d, 2p) level of theory. We have compared our calculated results with the experimentally obtained values and found that both are in close agreement with each other. We have used the gauge-invariant atomic orbital (GIAO) approach to calculate the NMR (13C and 1H) chemical shifts using Gaussian 09 package. TD-DFT (time-dependent DFT) approach has been used to simulate the electronic spectra of the title compound in order to account for excited states. Other molecular properties such as HOMO-LUMO energies, NBO analysis, and PED distribution analysis have been studied and reported using DFT/B3LYP/6-311++G(2d, 2p) level of theory.

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Martínez-Cifuentes, Maximiliano, Matías Monroy-Cárdenas, Juan Millas-Vargas, Boris Weiss-López, and Ramiro Araya-Maturana. "Assessing Parameter Suitability for the Strength Evaluation of Intramolecular Resonance Assisted Hydrogen Bonding in o-Carbonyl Hydroquinones." Molecules 24, no. 2 (2019): 280. http://dx.doi.org/10.3390/molecules24020280.

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Intramolecular hydrogen bond (IMHB) interactions have attracted considerable attention due to their central role in molecular structure, chemical reactivity, and interactions of biologically active molecules. Precise correlations of the strength of IMHB’s with experimental parameters are a key goal in order to model compounds for drug discovery. In this work, we carry out an experimental (NMR) and theoretical (DFT) study of the IMHB in a series of structurally similar o-carbonyl hydroquinones. Geometrical parameters, as well as Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) parameters for IMHB were compared with experimental NMR data. Three DFT functionals were employed to calculated theoretical parameters: B3LYP, M06-2X, and ωB97XD. O…H distance is the most suitable geometrical parameter to distinguish among similar IMHBs. Second order stabilization energies ΔEij(2) from NBO analysis and hydrogen bond energy (EHB) obtained from QTAIM analysis also properly distinguishes the order in strength of the studied IMHB. ΔEij(2) from NBO give values for the IMHB below 30 kcal/mol, while EHB from QTAIM analysis give values above 30 kcal/mol. In all cases, the calculated parameters using ωB97XD give the best correlations with experimental 1H-NMR chemical shifts for the IMHB, with R2 values around 0.89. Although the results show that these parameters correctly reflect the strength of the IMHB, when the weakest one is removed from the analysis, arguing experimental considerations, correlations improve significantly to values around 0.95 for R2.

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Matin, Mohammad A., Mohammad Alauddin, Tapas Debnath, M. Saiful Islam, and Mohammed A. Aziz. "DFT and TD-DFT Study of [Tris(dithiolato)M]3- Complexes[M= Cr, Mn and Fe]: Electronic Structures, Properties and Analyses." Dhaka University Journal of Science 67, no. 1 (2019): 63–68. http://dx.doi.org/10.3329/dujs.v67i1.54576.

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Using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods, transition metal complexes of benzene-1, 2-dithiolate (L2-) ligand from Cr to Fe have been studied theoretically. The ground state geometries, binding energies, UV-Visible spectra (UV-Vis), frontier molecular orbitals (FMOs) analysis, charge analysis and natural bond orbital (NBO) have been calculated. The structural parameters are in good accord with the experimental data. The metal-ligand binding energies are one (1) order of magnitude higher than the physisorption energy of a benzene-1, 2-dthiolate molecule on a metallic surface. In accordance with experiment the calculated electronic spectra of these tris complexes show bands at 565, 559 and 546 nm for Cr3+, Mn3+, and Fe3+ respectively which are mainly qualified to ligand-to metal charge transfer (LMCT) transitions. The electronic properties analysis demonstrate that the highest occupied molecular orbital (HOMO) is mostly centered on metal coordinated sulfur atoms whereas the lowest unoccupied molecular orbital (LUMO) is mainly located on the metal surface. By calculating natural bond orbital (NBO), the intramolecular interactions and electron delocalization was obtained. The results of NBO analysis illustrated the significant charge transfer from sulfur to central metal ions, as well as to the benzene of the complex. The calculated charges on metal ions are also reported at various charge schemes. The calculations show encouraging agreement with the available experimental data. Dhaka Univ. J. Sci. 67(1): 63-68, 2019 (January)

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Bihain, Murielly Fernanda Ribeiro, Raissa Santos Sousa, Sílvio Quintino de Aguiar Filho, and Douglas Henrique Pereira. "Cálculos teóricos para elucidação eletrônica de barreiras rotacionais: teoria e aplicações." Journal of Biotechnology and Biodiversity 8, no. 2 (2020): 136–47. http://dx.doi.org/10.20873/jbb.uft.cemaf.v8n2.bihain.

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Cálculos teóricos de estrutura eletrônica são ferramentas da química teórica. Sua importância se estende desde a análises de rotação, hiperconjugação, efeitos estéricos a cálculos de localização de orbitais, nível de energia e interação entre orbitais ligantes e antiligantes. As teorias como Natural Bond Orbital (NBO), Quantum Theory of Atoms in Molecules (QTAIM), e Energetic Decomposition Analysis (EDA), são exemplos de ferramentas teóricas que descrevem a estrutura eletrônica de moléculas e sólidos. Neste contexto o objetivo do artigo foi descrever as abordagens teóricas do NBO, EDA e QTAIM de forma breve com suas aplicações no sistema químico hidrazina e em trabalhos teóricos encontrados na literatura que reforçam a elucidação dos efeitos estereoeletrônicos.

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Laconsay, Croix J., Ka Yi Tsui, and Dean J. Tantillo. "Tipping the balance: theoretical interrogation of divergent extended heterolytic fragmentations." Chemical Science 11, no. 8 (2020): 2231–42. http://dx.doi.org/10.1039/c9sc05161a.

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We interrogate a type of heterolytic fragmentation called a ‘divergent fragmentation’ using density functional theory (DFT), natural bond orbital (NBO) analysis, ab initio molecular dynamics (AIMD), and external electric field (EEF) calculations.

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Vijayachamundeeswari, S. P., B. Yagna Narayana, S. Jone Pradeepa, and N. Sundaraganesan. "Vibrational analysis, NBO analysis, NMR, UV–VIS, hyperpolarizability analysis of Trimethadione by density functional theory." Journal of Molecular Structure 1099 (November 2015): 633–43. http://dx.doi.org/10.1016/j.molstruc.2015.06.079.

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Krivitskaya, Alexandra V., Maria G. Khrenova, and Alexander V. Nemukhin. "Two Sides of Quantum-Based Modeling of Enzyme-Catalyzed Reactions: Mechanistic and Electronic Structure Aspects of the Hydrolysis by Glutamate Carboxypeptidase." Molecules 26, no. 20 (2021): 6280. http://dx.doi.org/10.3390/molecules26206280.

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We report the results of a computational study of the hydrolysis reaction mechanism of N-acetyl-l-aspartyl-l-glutamate (NAAG) catalyzed by glutamate carboxypeptidase II. Analysis of both mechanistic and electronic structure aspects of this multistep reaction is in the focus of this work. In these simulations, model systems are constructed using the relevant crystal structure of the mutated inactive enzyme. After selection of reaction coordinates, the Gibbs energy profiles of elementary steps of the reaction are computed using molecular dynamics simulations with ab initio type QM/MM potentials (QM/MM MD). Energies and forces in the large QM subsystem are estimated in the DFT(PBE0-D3/6-31G**) approximation. The established mechanism includes four elementary steps with the activation energy barriers not exceeding 7 kcal/mol. The models explain the role of point mutations in the enzyme observed in the experimental kinetic studies; namely, the Tyr552Ile substitution disturbs the “oxyanion hole”, and the Glu424Gln replacement increases the distance of the nucleophilic attack. Both issues diminish the substrate activation in the enzyme active site. To quantify the substrate activation, we apply the QTAIM-based approaches and the NBO analysis of dynamic features of the corresponding enzyme-substrate complexes. Analysis of the 2D Laplacian of electron density maps allows one to define structures with the electron density deconcentration on the substrate carbon atom, i.e., at the electrophilic site of reactants. The similar electronic structure element in the NBO approach is a lone vacancy on the carbonyl carbon atom in the reactive species. The electronic structure patterns revealed in the NBO and QTAIM-based analyses consistently clarify the reactivity issues in this system.

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Brenner, Valérie, Eric Gloaguen, and Michel Mons. "Rationalizing the diversity of amide–amide H-bonding in peptides using the natural bond orbital method." Physical Chemistry Chemical Physics 21, no. 44 (2019): 24601–19. http://dx.doi.org/10.1039/c9cp03825f.

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Natural bond orbital (NBO) analysis of electron delocalization in a series of capped isolated peptides is used to diagnose amide–amide H-bonding and backbone-induced hyperconjugative interactions, and to rationalize their spectral effects.

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Melhi, Saad, Mahmoud A. Bedair, Eid H. Alosaimi, Ayman A. O. Younes, Walaa H. El-Shwiniy, and Ahmed M. Abuelela. "Effective corrosion inhibition of mild steel in hydrochloric acid by newly synthesized Schiff base nano Co(ii) and Cr(iii) complexes: spectral, thermal, electrochemical and DFT (FMO, NBO) studies." RSC Advances 12, no. 50 (2022): 32488–507. http://dx.doi.org/10.1039/d2ra06571a.

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Two Co(ii) and Cr(iii) complexes were synthesized, characterized and examined as corrosion inhibitors. The electrochemical data showed high inhibition efficiencies with mixed-type behavior. FMO and NBO were considered for the computational analysis.

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Morita, Kenji, and Bun Tsuchiya. "Dynamic Behavior of Li in Solid-State Li-Ion Batteries Studied using MeV Ion Beam Analysis Techniques." Journal of Energy and Power Technology 03, no. 02 (2021): 1. http://dx.doi.org/10.21926/jept.2102029.

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In this review, various studies on the Li depth profiles of metal/electrolyte/metal capacitors and batteries of Au/LCO/LATP/Pt, LCO/LiPON/Si, and LMO/LiPON/NbO with different metal electrodes at both sides (by bias; LCO =LiCoO2, LATP =Li3.1Al0.86Ti1.14Ge1.27P1.73O12, LMO =LiMn2O4, NbO = Nb2O5) using the in-situ reflection ERD (ERD) technique with 9MeV O+4 ion beam and transmission ERD (TERD) technique with 5MeV He+2 ion beam, respectively, are described. For capacitors, the transport fraction of Li-ion in the electrolyte is less than unity. The Li atoms diffuse in the direction opposite to the ion. It has been shown that the batteries are rechargeable. On the other hand, it is observed that an anomalous over-charging takes place when the batteries are over-biased (Si/LiPON/LCO and LMO/LiPON/NbO), and strong reactions of Li with the metal electrodes take place under these conditions. The anomaly observed is explained in terms of the imbalance in the capacities of Li in anode and cathode, which can be attributed to the sizeable amounts of hydrogen present as an impurity during the fabrication of the battery. This is because hydrogen can potentially reduce the capacity of Li in both anode and cathode. The reactions of Li with metal electrodes are discussed in terms of the transport fraction of Li ions (less than unity) and the difference in the work functions of metal electrodes at both sides. Finally, it is noted that the removal of hydrogen in batteries can potentially improve safety, efficiency, and lifetime. These can be achieved by reducing the reaction of Li with metal electrodes. The recoil-scatter method in the TERD technique can measure the Li depth profile in the absence of background yields.

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Ghafouri, Reza, Fatemeh Ektefa, and Mansour Zahedi. "Characterization of Hydrogen Bonds in the End-Functionalized Single-Wall Carbon Nanotubes: A DFT Study." Nano 10, no. 03 (2015): 1550036. http://dx.doi.org/10.1142/s1793292015500368.

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A systematic computational study is carried out to shed some light on the structure of semiconducting armchair single-wall carbon nanotubes (n, n) SWCNTs, n = 4, 5 and 6, functionalized at the end with carboxyl (– COOH ) and amide (– CONH 2) from the viewpoint of characterizing the intramolecular hydrogen bondings at the B3LYP/6-31++G(d, p) level. Geometry parameters display different types of intramolecular hydrogen bonding possibilities in the considered functionalized SWCNTs. All of the hydrogen bondings are confirmed by natural bonding orbitals (NBO) analysis as well as nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) parameters. Based on NBO analysis, the calculated [Formula: see text] delocalization energies E(2), 1.15 kcal/mol to 7.04 kcal/mol, are in direct relation with the hydrogen bonding strengths. Differences in the chemical shielding principal components of 13 C and 17 O nuclei correlate well with the strengths of the hydrogen bondings. Participating in stronger hydrogen bondings, a larger SWCNT has a decreasing effect on 13 C (= O ) and 17 O isotropic chemical shieldings, σiso, consistent with the NBO analysis. The considerable changes of 13 C /17 O σiso can be interpreted as a result of shielding tensor component orientation. The 13 C (= O ) and 17 O quadrupole coupling constants C Q decrease under the effect of hydrogen bonding while asymmetry parameters ηQ significantly increase, indicating that 17 O ηQ is more sensitive to hydrogen bondings.

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Wang, Ben, Min Gao, Kohei Uosaki, and Tetsuya Taketsugu. "A quantum chemical study of substituent effects on CN bonds in aryl isocyanide molecules adsorbed on the Pt surface." Physical Chemistry Chemical Physics 22, no. 21 (2020): 12200–12208. http://dx.doi.org/10.1039/d0cp00760a.

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A periodicity implemented scheme of NBO theory and normal mode analysis has been employed to investigate the chemical bond strength tendency for aryl isocyanide molecules with different para-substituted groups adsorbed on the Pt(111) surface.

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Abramov, Pavel A., and Maxim N. Sokolov. "Not So Similar: Different Ways of Nb(V) and Ta(V) Catecholate Complexation." Molecules 28, no. 13 (2023): 4912. http://dx.doi.org/10.3390/molecules28134912.

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The reactions between catechol (H2cat) and niobium(V) or tantalum(V) precursors in basic aqueous solutions lead to the formation of catecholate complexes of different natures. The following complexes were isolated and characterized by single-crystal X-ray diffraction (SCXRD): (1) (NH4)3[NbO(cat)3]∙4H2O; (2) K2[Nb(cat)3(Hcat)]·2H2cat·2H2O; (3) Cs3[NbO(cat)3]·H2O; (4) (NH4)4[Ta2O(cat)6]·3H2O; (5) Cs2[Ta(cat)3(Hcat)]·H2cat; (6) Cs4[Ta2O(cat)6]·7H2O. The isolated crystalline products were characterized by elemental analysis, X-ray powder diffraction (XRPD), FTIR, and TGA. The structural features of these complexes, such as {Ta2O} unit geometry, Cs-π interactions, and crystal packing effects, are discussed.

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Shahab, Siyamak, Masoome Sheikhi, Liudmila Filippovich, et al. "Molecular Investigations of the Newly Synthesized Azomethines as Antioxidants: Theoretical and Experimental Studies." Current Molecular Medicine 19, no. 6 (2019): 419–33. http://dx.doi.org/10.2174/1566524019666190509102620.

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: In this study, the antioxidant property of new synthesized azomethins has been investigated as theoretical and experimental. Methods and Results: Density functional theory (DFT) was employed to investigate the Bond Dissociation Enthalpy (BDE), Mulliken Charges, NBO analysis, Ionization Potential (IP), Electron Affinities (EA), HOMO and LUMO energies, Hardness (η), Softness (S), Electronegativity (µ), Electrophilic Index (ω), Electron Donating Power (ω-), Electron Accepting Power (ω+) and Energy Gap (Eg) in order to deduce scavenging action of the two new synthesized azomethines (FD-1 and FD-2). Spin density calculations and NBO analysis were also carried out to understand the antioxidant activity mechanism. Comparison of BDE of FD-1 and FD-2 indicate the weal antioxidant potential of these structures. Conclusion: FD-1 and FD-2 have very high antioxidant potential due to the planarity and formation of intramolecular hydrogen bonds.

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Journal articles on the topic 'NBO analysis'

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