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Journal articles on the topic 'Am1 method'

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Published: 4 June 2021

Last updated: 1 February 2022

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1

Mahboub, Radia. "Structural Conformational Study of Eugenol Derivatives Using Semiempirical Methods." Advances in Chemistry 2014 (October 20, 2014): 1–5. http://dx.doi.org/10.1155/2014/490358.

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We investigated the conformational structure of eugenol and eugenyl acetate under torsional angle effect by performing semiempirical calculations using AM1 and PM3 methods. From these calculations, we have evaluated the strain energy of conformational interconversion. To provide a better estimate of stable conformations, we have plotted the strain energy versus dihedral angle. So, we have determined five geometries of eugenol (three energy minima and two transition states) and three geometries of eugenyl acetate (two energy minima and one transition state). From the molecular orbital calculations, we deduce that the optimized trans form by AM1 method is more reactive than under PM3 method. We can conclude that both methods are efficient. The AM1 method allows us to determine the reactivity and PM3 method to verify the stability.

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2

Shephard, MJ, and MN Paddonrow. "Conformational Analysis of C60 Ball-and-Chain Molecules: a Molecular Orbital Study." Australian Journal of Chemistry 49, no. 3 (1996): 395. http://dx.doi.org/10.1071/ch9960395.

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A computational study of the conformational analysis of a series of C60 ball-and-chain bichromophoric molecules (1)-(6) has been carried out by means of the AM1 and HF/3-21G//AM1 theoretical methods. It is found that the AM1 method underestimates both the relative conformational energies and the magnitude of the energy barriers folded and extended conformers. In contrast, the HF/3-21G//AM1 method gives reasonable values for these quantities. The HF/3-21G//AM1 calculated energy differences between the folded and extended conformers of systems (2)-(5) are less than 5 kJ/mol and the barriers to their interconversion are c. 30 kJ/mol. The conformational bias in these systems may be modified by the judicious placement of methyl groups in the region of the hydrocarbon chain closest to the C60 cage. It is found that the length of the chain and the nature of the non-C60. chromophore have little effect on the conformational energetics.

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3

Bureš, Michal, and Jaroslav Bezus. "Study of Hydrogen Bonding in Carboxylic Acids by the MNDO/M Method." Collection of Czechoslovak Chemical Communications 59, no. 6 (1994): 1251–60. http://dx.doi.org/10.1135/cccc19941251.

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The semiempirical methods MNDO/M, AM1 and PM3 were applied to the study of hydrogen bonds in carboxylic acids. The calculated hydrogen bond lengths and enthalpies of dimerization were compared with experimental data. The AM1 method fails to properly describe systems with strong hydrogen bonds. The PM3 method predicts the hydrogen bond lengths correctly but underestimates systematically the enthalpies of dimerization. MNDO/M appears to be a promising method for the treatment of association of carboxylic acids.

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4

Werstiuk, N. H., K. B. Clark, and W. J. Leigh. "Conformational analysis and structure elucidation of 2,3-dimethyl- and 2,4-dimethyl-2,4-hexadienes by AM1 and He(I) ultraviolet photoelectron spectroscopy." Canadian Journal of Chemistry 68, no. 11 (November 1, 1990): 2078–84. http://dx.doi.org/10.1139/v90-317.

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A study of (E)-2,3-dimethyl-2,4-hexadiene (E-3) and (Z)-2,3-dimethyl-2,4-hexadiene (Z-3) by the semiempirical computational method AM1 and He(I) ultraviolet photoelectron spectroscopy (UPS) has established that this combination of AM1/UPS will be generally useful for detailing conformational and electronic properties of alkyl-substituted 1,3-dienes. This method was used to elucidate the structures of the stereoisomeric 2,4-dimefhyl-2,4-hexadienes obtained from the photolysis of 1,3,3,4-tetramethylcyclobutene (2). Keywords: 2,3- and 2,4-dimethyl-2,4-hexadienes, conformational analysis, AM1, He(I) photoelectron spectroscopy.

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5

Robidas, Raphaël, Claude Y. Legault, and Stefan M. Huber. "A low cost, high accuracy method for halogen bonding complexes." Physical Chemistry Chemical Physics 23, no. 4 (2021): 3041–49. http://dx.doi.org/10.1039/d0cp05614f.

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6

Fabian, Walter M. F. "Tautomerism in Five-membered Nitrogen Heterocycles. A Test of the Reliability of Semiempirical (AMI, PM3, MNDO) Quantum Chemical Methods." Zeitschrift für Naturforschung A 45, no. 11-12 (December 1, 1990): 1328–34. http://dx.doi.org/10.1515/zna-1990-11-1216.

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AbstractThe reliability of three popular semiempirical quantum chemical methods (AM1, PM3, MNDO) for the treatment of tautomeric equilibria is tested in a series of five-membered nitrogen heterocycles. The known flaw of MNDO to overestimate the stability of compounds with two or more adjacent pyridine-like lone pairs is also present in AM1 and to a somewhat lesser extent in PM3. Tautomeric species differing in the number of adjacent pyridine-like lone pairs, thus, cannot be adequately treated by these semiempirical methods. Both AM1 as well as PM3, however, represent major improvements over MNDO in the case of lactam-lactim tautomerism. The stability of N-oxides as compared to N-hydroxy tautomers seems to be overestimated by the PM3 method. All three semiempirical methods yield quite reliable ionization potentials and dipole moments.

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7

Palafox, M. Alcolea, M. Gil, and J. L. Núñez. "Spectroscopy of p-Methoxybenzoic Acid: An AM1 and ab Initio Study." Applied Spectroscopy 48, no. 1 (January 1994): 27–36. http://dx.doi.org/10.1366/0003702944027660.

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The vibrational spectra of p-methoxybenzoic acid (anisic acid) were calculated and compared with the experimental spectra. All measured bands in the IR and Raman spectra were interpreted in terms of calculated vibrations from the AM1 and 4–21G* methods, and their frequencies were correlated. Several scale coefficients were used to improve the theoretical spectra. The optimum geometric parameters were also computed with the AM1 semiempirical method and with the 4–21G* ab initio procedure.

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8

Xu, Lingjia, Liangliang Zhu, Shi Wu, Xiaopeng Chen, and Qiwen Teng. "Hydrogen-bonded assembly and binding affinity of the multi-point acceptor and isophthalic acid." Open Chemistry 4, no. 4 (December 1, 2006): 732–42. http://dx.doi.org/10.2478/s11532-006-0038-9.

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AbstractSupermolecular complexes formed by oligophenyleneethynylene derivatives and isophthalic acid were studied using AM1 method to obtain binding energy. Electronic spectra and IR spectra of the complexes were calculated by INDO/CIS and AM1 methods based on AM1 geometries. Results indicated that the dimer could be formed by the monomers via hydrogen bonding because of the negative binding energy. Binding energy of the complexes was affected by electronegativity and steric effects of the substituents. The first UV absorptions and IR frequencies of N-H bonds of the complexes were both red-shifted compared with those of the monomers. The complexes could bind small molecules via hydrogen bonds, resulting in the change in UV absorptions and an increase in IR frequencies of N-H bonds.

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9

UDOMVECH, ANURAK, TEERAKIAT KERDCHAROEN, VUDHICHAI PARASUK, YUTHANA TANTIRUNGROTECHAI, and TANAKORN OSOTCHAN. "ELECTRONIC STRUCTURE OF THE FINITE-SIZED SINGLE-WALLED CARBON NANOTUBES." International Journal of Nanoscience 02, no. 03 (June 2003): 141–52. http://dx.doi.org/10.1142/s0219581x03001176.

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The effects of tubule length and terminal capping on the geometrical and electronic properties of finite-sized zig-zag (9, 0) single-walled carbon nanotubes (SWNT), which length varying from 2 up to 12 unit cells (~50 Å), were investigated using molecular mechanics, semi-empirical methods (AM1 and EHMO) and density functional theory (B3LYP). AM1 method indicates how the nanotube ends are capped affects strongly the tubule geometric parameters. Although these effects seem to decrease exponentially as the tube gets longer, the converging values for C–C bond length in the open- and closed-end structures are slightly different. It was learned that combination of low-level methods like AM1 and EHMO (which tend to overestimate and underestimate the HOMO–LUMO energy gap, respectively) together with high-level method such as DFT is efficient to estimate band gap for finite-sized nanostructures. The HOMO–LUMO energy gaps obtained from semi-empirical and DFT methods decrease as the tubule length increases. Terminal capping also affects strongly the electronic structure of finite-sized nanotube. Thus, closing the terminal ends by fullerene hemisphere broadens the energy gap of the hydrogen-saturated open-end nanotube. Although the open-end SWNT has much lower AM1 HOMO–LUMO energy gap than the closed-end SWNT, these orbitals unfortunately are localized near the capping hydrogen, thereby do not provide conducting channels for electrons. By comparing only the delocalized frontier orbitals, both structures yield closer energy gap. Analysis of the energy gap based on EHMO, AM1 and DFT results suggests that both open- and closed-end finite-sized SWNT are semiconductor, in agreement with recent scanning tunneling experiment. It was found that the slight accumulated negative charges are likely to locate at the nanotube's fullerene tips.

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10

El Merbouh, B., M. Bourjila, R. Tijar, R. Drissi El Bouzaidi, A. El Gridani, and M. El Mouhtadi. "Conformational space analysis of neutral and protonated glycine using a genetic algorithm for multi-modal search." Journal of Theoretical and Computational Chemistry 13, no. 08 (December 2014): 1450067. http://dx.doi.org/10.1142/s0219633614500679.

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The genetic algorithm based on the Multi-Niche Crowding (MNC) method is used with the semi-empirical methods AM1 and PM3 in order to scan the potential energy surface (PES) of neutral and protonated glycine. The algorithm is implemented as a package of programs interfaced with MOPAC and piloted by scripts. Both methods AM1 and PM3 located six minima on the PES of neutral glycine and seven on the protonated glycine one, of which three are those of the N -protonated form and four of the O -protonated one.

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11

Werstiuk, Nick Henry, and David Andrew. "A study of thermodynamic acidities of enols with the semiempirical computational method AM1." Canadian Journal of Chemistry 68, no. 8 (August 1, 1990): 1467–69. http://dx.doi.org/10.1139/v90-224.

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Using the semiempirical computational method AM1 we have computed the enthalpies of ionization of enols 1–21 and correlated these values with solution and estimated pKa's. From this initial study it appears that, in general, it is possible to predict the pK's of acyclic enols within ± 1 pKa unit. On the basis of this correlation we predict the pKa's of 1-hydroxy-1,3-butadiene (3-butenal enol) (9.7) and 1,1-difluoroacetone enol (9.6) and suggest that the previously estimated pKa of 1,1-dichloroacetone enol (6.2) is low by approximately 3 pK units. We find computationally (this has been established experimentally) that the Z-enol of phenylacetaldehyde is less acidic than the E-enol. Keywords: enols, acidities, computational studies, AM1.

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12

Shephard, MJ, and MN Paddonrow. "A Caveat Concerning the Use of the AM1 and PM3 Semiempirical Methods in Calculating Conformational Preferences in Acyclic Amines and Saturated Azaheterocycles." Australian Journal of Chemistry 46, no. 4 (1993): 547. http://dx.doi.org/10.1071/ch9930547.

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A theoretical investigation of the conformational analysis of several acyclic amines, N- alkylated saturated azaheterocycles and alkylcyclohexanes (alkyl = Me, Et, isopropyl, t-butyl) has been carried out by using the MNDO, AM1 and PM3 semiempirical methods. It is found that all three methods correctly predict, qualitatively, the conformational preferences in alkylcyclohexanes, although the PM3 method underestimates the conformational energy for the t-butyl group by as much as 13 kJ/mol. Both AM1 and PM3 overestimate the conformational energy of the nitrogen lone pair to the extent that it exceeds that of the isopropyl group and (in the case of PM3) the t-butyl group, thereby leading to erroneous predictions of favoured conformations in amines and azaheterocycles . Thus, axial N-alkylpiperidines are predicted to be more stable than the equatorial conformers. Thus, application of the AM1 and PM3 methods to the conformational analysis of molecules containing amine functionalities is not recommended. Although the MNDO method gives a qualitative account of the conformational analysis of such molecules, with the exception of hexahydropyridazines and hexahydropyrimidines, the resulting conformational energies and molecular geometries are in poor agreement with experimental data.

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13

Palafox, M. Alcolea. "Conformational study of several diazabicyclanols by the AM1 method." Journal of Molecular Structure: THEOCHEM 257, no. 3-4 (May 1992): 259–78. http://dx.doi.org/10.1016/0166-1280(92)85044-l.

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14

Jaworska, Maria, Jarosaw Polański, and Aleksander Ratajczak. "Conformational analysis of phenylsulphonylalkanoic acids with the AM1 method." Journal of Molecular Structure: THEOCHEM 283 (July 1993): 207–11. http://dx.doi.org/10.1016/0166-1280(93)87131-v.

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15

Nasution, Hasmalina, Nur Enizan, Nurlaili Nurlaili, and Jufrizal Syahri. "Design of Trolox Compounds as Antioxidant and Their Analysis Using Quantitative Structure Activity Relationship." Acta Chimica Asiana 3, no. 2 (October 18, 2020): 181. http://dx.doi.org/10.29303/aca.v3i2.40.

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Antioxidant compound can inhibit the oxidation of lipids and other biomolecules. The role of antioxidants is very important in neutralizing and destroying free radicals that can cause the damage to cells in the body. This research was carried out to design trolox derivate compounds as antioxidants using the QSAR method. The semi empirical AM1(Austin Model 1)method was used to generate the QSAR model. The statistical analysis result using multiple linier regression methods revealed thet antioxidant activity was influenced by the descriptors of qC1, qC4, qO7, qC13 and qO18. The QSAR equation model obtained was log IC50 = 0.821 + 7.067 (qC1) + 2.585 (qC4) + 4.812 (qO7) – 5.363 (qC13) – 0.887 (qO18) with the best predicted IC50 value was 4.699 µM. Keywords: Antioxidants, QSAR, semi empirical AM1, trolox

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16

Hernando, José María, José Joaquín Quirante, and Fernando Enríquez. "Study of the Interconversion of Isomers of [16]annulene by the AM1 Method." Collection of Czechoslovak Chemical Communications 57, no. 1 (1992): 1–6. http://dx.doi.org/10.1135/cccc19920001.

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The AM1 method was used to carry out a theoretical study of different isomers of [16]annulene and of the reversible transformation between them preserving the molecular periphery. Transition states were located on the corresponding potential energy hypersurface.

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17

Breza, Martin, and Vlasta Brezová. "AM1 Calculations of Spin Distribution in Hydroxyanthrasemiquinones." Collection of Czechoslovak Chemical Communications 60, no. 7 (1995): 1081–93. http://dx.doi.org/10.1135/cccc19951081.

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The AM1 method was used to obtain the optimum geometries of hydroxyanthrasemiquinones. The relation between the spin distribution data obtained by analysis of EPR spectra and by AM1 calculations depends on the position of the C atom within the aromatic skeleton, on its spin density sign and on its position relative to OH substituents. Complete annihilation of higher spin state contaminations is insufficient to eliminate the significant discrepancies between the theoretical and experimental data.

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18

Jotani, Mukesh M. "Crystal Structure Optimization and Semi-Empirical Quantum Chemical Calculations of N-(3,4-Dichlorophenyl)-3-Oxo-Butanamide." Advanced Materials Research 620 (December 2012): 82–86. http://dx.doi.org/10.4028/www.scientific.net/amr.620.82.

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The crystal structure of N-(3,4-Dichlorophenyl)-3-oxobutanamide (I) is optimized by semi-empirical methods using MOPAC2009 program. The optimized geometries from both Austin Model 1 (AM1) and Parametrization Model 6 (PM6) describe the conformational discrepancy and crystal packing. The energy minimized structures from both the models are in good agreement with X-ray crystal data. The intramolecular charge transfer interactions are studied from the molecular orbital calculations. The parametric molecular electrostatic potential (PMEP) calculated by AM1 semi-empirical method shows the involvement of oxygen and chlorine atoms in the crystal packing interactions. The aromaticity of phenyl ring in the structure is determined using HOMED calculations.

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19

Wen-Yuan, Xu, Liu Gou-Sheng, Peng Yi-Yuan, and Hong San-Guo. "AM1 Method Study of Thermolyses of Formacyl and Benzoyl Azides." Acta Physico-Chimica Sinica 14, no. 07 (1998): 669–72. http://dx.doi.org/10.3866/pku.whxb19980719.

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20

Dixon, Richard W., Joseph M. Leonard, and Warren J. Hehre. "A Continuum Solvation Model for the AM1 Semi-Empirical Method." Israel Journal of Chemistry 33, no. 4 (1993): 427–34. http://dx.doi.org/10.1002/ijch.199300049.

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21

Davis, Larry P., Larry W. Burggraf, and Donn M. Storch. "Hydration of small anions: Calculations by the AM1 semiempirical method." Journal of Computational Chemistry 12, no. 3 (April 1991): 350–58. http://dx.doi.org/10.1002/jcc.540120308.

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22

Martí, Josep, Agustí Lledós, Juan Bertrán, and Miquel Duran. "Vibrational Stark effect: Theoretical determination through the semiempirical AM1 method." Journal of Computational Chemistry 13, no. 7 (September 1992): 821–29. http://dx.doi.org/10.1002/jcc.540130705.

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23

Barrett, Rosemary A., and Robert J. Meier. "The calculation of molecular entropy using the semiempirical AM1 method." Journal of Molecular Structure: THEOCHEM 363, no. 2 (April 1996): 203–9. http://dx.doi.org/10.1016/0166-1280(95)04438-8.

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24

Hong, San-Guo, and Shen Wang. "AM1 method study of the thermolyses of aryl t-butylamines." Journal of Molecular Structure: THEOCHEM 336, no. 1 (June 1995): 85–90. http://dx.doi.org/10.1016/0166-1280(95)91279-h.

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25

Chen, Sicong, Qiwen Teng, and Shi Wu. "Theoretical studies on the binding affinities of β-cyclodextrin to small molecules and monosaccharides." Open Chemistry 4, no. 2 (June 1, 2006): 223–33. http://dx.doi.org/10.2478/s11532-006-0013-5.

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AbstractEquilibrium geometries and electronic structures of complexes between β-cyclodextrin (β-CD) and some small molecules as well as monosaccharides were investigated by Austin Model 1 (AM1) to obtain binding energy of the complexes. It was indicated that β-CD could bind the structurally similar solvent molecules and monosaccharides because of the negative binding energy of the complexes, and especially could show the chiral binding ability to monosaccharides with more hydroxyl groups, due to its chiral characteristics. The complexes were stabilized by the hydrogen bonding between β-CD and guests. Based on the AM1 optimized geometries, the IR spectra were calculated by AM1 method. Vibration frequencies of O-H bonds in the guests were red-shifted owing to the weakening of the O-H bonds with the formation of the complexes.

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26

Gupta, Pradeep Kumar, and Kishor Arora. "Comparative Studies of Infrared Spectral Simulation of Some Benzoyl Derivatives of N-Heterocyclic Compounds Using Semi-Empirical Methods." Asian Journal of Chemistry 32, no. 10 (2020): 2463–68. http://dx.doi.org/10.14233/ajchem.2020.22643.

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Simulation studies based on ab initio, semi-empirical or density functional (DFT) calculations are now becoming common among the researchers who are pursuing their intereset in theoretical chemistry. These studies are based on quantum chemical softwares. These studies provide better insight for the structural and other parameters of the compounds. The present paper includes the studies on synthesis or procurement along with the simulated IR spectra of some benzoyl derivatives of N-heterocyclic compounds viz. 2-aminopyridine, 4-aminoantipyrine, 2-aminopyrimidine or 3-aminopyridine using four different AM1, PM3, MNDO and ZINDO1 semi-empirical methods. Among the methods used for the study, AM1 method is more reliable and more accurate so far as the prediction of spectral results is concerned.

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27

Wolk, J. L., M. R. Hajnal, S. Hoz, R. M. Tarkka, and E. Buncel. "Relative reactivity of three oxygen lone pairs of an α-nucleophile in SN2 reactions." Canadian Journal of Chemistry 68, no. 7 (July 1, 1990): 1182–85. http://dx.doi.org/10.1139/v90-182.

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The SN2 reaction of H2C=NO− with CH3Cl was investigated at the AM1, STO-3G, and 6-31 + G* levels. Three modes of approach of CH3Cl to the oxygen of the nucleophile were examined: syn and anti to the lone pair on the nitrogen in the molecular plane, and an approach along the π system of the oximate anion. The AM1 method differed markedly from the two abinitio methods, both in the reactivity order of the three geometries as well as in the relative stabilities of the products. The reactivity order calculated at the STO-3G and the 6-31 + G* levels was syn > π > anti (AM1 order: anti > syn > π). Product stability order calculated by the two abinitio methods was syn > anti > π (AMI order: anti > syn > π). Excellent agreement was obtained between percent bond elongations at the transition state predicted by the equation suggested by Shaik, Schlegel, and Wolfe, and the activation barriers calculated at the 6-31 + G* level. The relevance of the calculations with respect to the α-effect is also discussed. Keywords: oxygen lone pairs, aximate, SN2, abinitio.

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28

Prakoso, Nurcahyo Iman, Lukman Hakim, and Nuri Hidayati. "Molecular Modeling of An Analog Of Curcumin Compounds Pentagamavunon-0 (PGV-0) And Pentagamavunon-1 (PGV-1) Through Computational Chemistry Methods Ab-Initio HF/4-31G." Chemical 3, no. 1 (December 31, 2017): 28–39. http://dx.doi.org/10.20885/ijcr.vol2.iss1.art4.

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Breast cancer is the second largest number of cancer cases in Indonesia, after cervical cancer. The growth of these cancer cells can be prevented with compounds Pentagamavunon-0 (PGV-0) and Pentagamavunon-1 (PGV-1). This compound is an analog of curcumin compounds that have anti breast cancer activity. Modeling the structure of compound PGV-0 and PGV-1 through computational chemistry methods Ab-initio HF/4-31G could be used to predict the geometry and structure elucidation spectra associated with pharmacological activity such as anticancer compounds theoretically.This research involves modeling the structures and spectra prediction calculation compounds PGV-0 and PGV-1 by computational chemistry methods Ab-initio HF/4-31G, using Gaussian03W. The result using Ab-initio HF/4-31G method then compared with data from experimental geometry and the results of calculations with AM1.The results showed that computational chemistry methods Ab-initio HF/4-31G calculations give better results for modeling the structure compared semiempirik method AM1.

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Foster, Michael E., and Karl Sohlberg. "A New Empirical Correction to the AM1 Method for Macromolecular Complexes." Journal of Chemical Theory and Computation 6, no. 7 (June 16, 2010): 2153–66. http://dx.doi.org/10.1021/ct100177u.

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30

Rodrigues, Carlos Rangel, Ricardo Bicca de Alencastro,, Eliezer Jesus Barreiro, and Carlos Alberto Manssour Fraga. "Proposal of a new PAF pharmacophoric map by the AM1 method." European Journal of Pharmaceutical Sciences 8, no. 4 (August 1999): 309–15. http://dx.doi.org/10.1016/s0928-0987(99)00029-9.

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Fleisher, M., V. Stonkus, L. Leite, and E. Lukevics. "Investigation of the 1,4-butanediol dehydrogenation over SiO2 using AM1 method." International Journal of Quantum Chemistry 100, no. 4 (2004): 407–11. http://dx.doi.org/10.1002/qua.20164.

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32

ALCOLEA PALAFOX, M. "ChemInform Abstract: Conformational Study of Several Diazabicyclanols by the AM1 Method." ChemInform 23, no. 35 (August 21, 2010): no. http://dx.doi.org/10.1002/chin.199235051.

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33

Saba, Adama, Síe Faustin Sib, and Jean-Pierre Aycard. "Isocoumarines: Structural Study by NMR and by AM1 Semi-Empirical Method." Spectroscopy Letters 28, no. 7 (October 1995): 1053–60. http://dx.doi.org/10.1080/00387019508009445.

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34

Yu, Pi Chun, Cheng Kuen Chen, Jin Lang Lin, Chih Ning Wu, and Hiroshi Matsuo. "High Aspect Ratio Contact Clean Study in 58nm Flash Device." Solid State Phenomena 145-146 (January 2009): 35–38. http://dx.doi.org/10.4028/www.scientific.net/ssp.145-146.35.

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In the conventional wet cleaning process of contact holes landing on the Si substrate and WSi metal gate, the ILD BPTEOS bowing and CD enlargement were often found by using dilute HF solution. With the device design rule decreasing, the CD size control and cleaning efficiency enhancement are highly demanded. In this work, the high aspect-ratio contact (AR~10) cleaning in single wafer (SW) tool was demonstrated in 58nm flash device. With the facilitation of nano-spray function to enhance particle removal efficiency (PRE), AM1 cleaning in SW tool can achieve the low contact resistance and tighten Rc distribution with less ILD film damage and lower CD enlargement. The parameter dependency of SW tool, including chemical injection method, nozzle swinging effect and nano-spray function, on contact resistance was also investigated. Compared to AM1 cleaning in bench tool, AM1 process in SW tool performs the larger process window for less ILD film damage at higher temperature and concentration.

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35

HASHIMOTO, HIDEKI, KINGO HATTORI, TAKASHI YAMADA, and TAKAYOSHI KOBAYASHI. "ELECTRO-ABSORPTION SPECTROSCOPY AND SEMI-EMPIRICAL MOLECULAR ORBITAL CALCULATIONS OF POLAR RETINOID ANALOGUES." International Journal of Modern Physics B 15, no. 28n30 (December 10, 2001): 3773–76. http://dx.doi.org/10.1142/s0217979201008639.

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Nonlinear polarizabilities of a series of polar retinoid analogues were determined experimentally by means of electro-absorption (Stark) spectroscopy. The dependence of the magnitude of nonlinear polarizabilities on polyene chain-lengths as well as on the strength of electron-accepting groups was systematically compared. Semi-empirical molecular orbital calculations using AM1 Hamiltonian (MNDO-AM1 method) could quantitatively predict the second (β) and the third (γ) order nonlinear polarizabilities of the present set of molecules except for the γ value of C20BDCInd. The real and imaginary parts of χ(3)(-ω;0,0,ω) spectra were calculated in order to account the figure of merit of the third-order nonlinear optical material.

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36

LEITE, Sérgio Roberto de Andrade. "Basicities of primary arylamines and calculated amine nitrogen electronic charges." Eclética Química 23 (1998): 71–80. http://dx.doi.org/10.1590/s0100-46701998000100006.

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Mülliken charges on nitrogen atoms were calculated for several arylamines, utilizing the AM1 Quantum Chemistry method, relating their values to experimental amine pKa . Direct relation between pKa and nitrogen charges was found. The amines energies of protonation, calculated by the same method, also correlate directly with these charges.

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37

Labidi, N. S. "Nonlinear Optical Properties of Novel Mono-O-Hydroxy Bidentate Schiff Base: Quantum Chemical Calculations." International Journal of Metals 2013 (December 17, 2013): 1–5. http://dx.doi.org/10.1155/2013/964328.

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The semiempirical AM1 SCF method is used to study the first static hyperpolarizabilities β of some novel mono-O-Hydroxy bidentate Schiff base in which electron donating (D) and electron accepting (A) groups were introduced on either side of the Schiff base ring system. Geometries of all molecules were optimized at the semiempirical AM1. The first static hyperpolarizabilities of these molecules were calculated using Hyperchem package. To understand this phenomenon in the context of molecular orbital picture, we examined the molecular HOMO and molecular LUMO generated via Hyperchem. The study reveals that the mono-O-Hydroxy bidentate Schiff bases have large β values and hence in general may have potential applications in the development of nonlinear optical materials.

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38

Wang, Zhongfa, and Shi Wu. "Electronic structures and spectra of conducting anthracene derivatives." Journal of the Serbian Chemical Society 73, no. 12 (2008): 1187–96. http://dx.doi.org/10.2298/jsc0812187w.

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Theoretical studies on anthracene and a series of its derivatives were performed using the AM1 method and DFT. Based on B3LYP/6-31G(d) optimized geometries, the electronic, IR and NMR spectra of anthracene oligomers were calculated using the Indo/Cis, AM1 and B3LYP/6-31G(d) methods, respectively. The energy gaps of the oligomers decreased and the main absorptions in the electronic spectra of the oligomers were red-shifted, whereas the IR frequencies for some of the C=C and C-H bonds were blue-shifted with increasing chain length and in the presence of substituents. The 13C-NMR chemical shifts of the bridged carbon atoms were upfield shifted in the presence of an electron-donating group, while the chemical shifts of the carbon atoms on the two side rings of the anthracene moiety shifted downfield in the presence of an electron-withdrawing group.

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39

Jotani, Mukesh M. "Crystal Structure Optimization and Semi-Empirical Quantum Chemical Calculations of Fused Bicyclic Heterocycles." Advanced Materials Research 1087 (February 2015): 59–63. http://dx.doi.org/10.4028/www.scientific.net/amr.1087.59.

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The crystal structures of two fused pyridine derivatives viz Ethyl 3-amino-6-phenyl-4-tolylfuro[2,3-b]pyridine-2-carboxylate (I) and Ethyl 3-amino-6-phenyl-4-tolylthieno[2,3-b] pyridine-2-carboxylate (II) were optimized by semi-empirical methods using MOPAC2009 program. The geometries optimized for both the structures from Austin Model 1 (AM1) and Parametrization Model 6 (PM6) describe the conformational discrepancy and crystal packing effects. The parametric molecular electrostatic potential (PMEP) calculated by AM1 semi-empirical method describe the involvement of nitrogen and oxygen atoms in the crystal packing interactions in both the structures. The frontier molecular orbitals highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) indicate the intramolecular charge transfer interactions. The HOMED indices computed for the phenyl rings in the structures describe the p-electron delocalization. The linear regression analysis shows good correlation between experimental and theoretical structures.

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40

Babkin, V. A., A. V. Ignatov, V. T. Fomichev, and G. E. Zaikov. "Quantum and Chemical Calculation of Methylcyclobutane and Ethylcyclobutane Molecules by AM1 Method." Vestnik Volgogradskogo gosudarstvennogo universiteta. Serija 10. Innovatcionnaia deiatel’nost’, no. 1 (March 2014): 41–46. http://dx.doi.org/10.15688/jvolsu10.2014.1.6.

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41

Heming, Xiao, Li Yumin, and Li Yongfu. "Theoretical Studies on the Mechanism of Hydrolysis of Nitroguanidine by AM1 Method." Propellants, Explosives, Pyrotechnics 23, no. 1 (February 1998): 23–27. http://dx.doi.org/10.1002/(sici)1521-4087(199802)23:1<23::aid-prep23>3.0.co;2-2.

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42

Dewar, Michael J. S., Eamonn F. Healy, Andrew J. Holder, and Yate-Ching Yuan. "Comments on a comparison of AM1 with the recently developed PM3 method." Journal of Computational Chemistry 11, no. 4 (May 1990): 541–42. http://dx.doi.org/10.1002/jcc.540110413.

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43

Turchaninov, V. K., A. I. Vokin, D. S. D. Toryashinova, A. F. Yermikov, K. B. Petrushenko, and S. E. Korostova. "Interpretation of photoelectron spectra in terms of the semi-empirical AM1 method." Russian Chemical Bulletin 42, no. 2 (February 1993): 275–79. http://dx.doi.org/10.1007/bf00697075.

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44

Danovich, David, Vechelslav Zakrzewski, and Elena Domnina. "Ionization energies of azines from green's function method in semiempirical AM1 approximation." Journal of Molecular Structure: THEOCHEM 188, no. 1-2 (June 1989): 159–66. http://dx.doi.org/10.1016/0166-1280(89)85034-1.

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45

Craik, DJ, PR Andrews, C. Border, and SLA Munro. "Conformational Studies of Thyroid Hormones. I. The Diphenyl Ether Moiety." Australian Journal of Chemistry 43, no. 5 (1990): 923. http://dx.doi.org/10.1071/ch9900923.

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Conformational flexibility round the diphenyl ether linkage in the thyroid hormones has been investigated by means of molecular orbital (AM1) and classical potential-energy calculations. The results obtained from these theoretical approaches are in qualitative agreement with those from n.m.r. spectroscopy, i.e., the barrier to rotation around this structural feature is sufficiently low to allow rapid interconversion between two stable conformers to occur at room temperature. Two pathways of rotation around the diphenyl ether bridge were explored and were both calculated to be approximately 14-15 kJ mol-1 by the AM1 method. This compares with the experimental barrier of 36 kJ mol-1. The potential-energy calculations gave barriers up to an order of magnitude larger which were inconsistent with experimental observations. A comparison of the AM1 data with results from previous studies with CNDO/2, which predicted a larger barrier, is also given. The detailed mode of interconversion around the two torsion angles involved in diphenyl ether rotation is investigated, as is the interplay of the bulky iodo substituents with the second aromatic ring during such conformational changes. The nature of torsion angle cooperation during rotations around this linkage is discussed.

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46

Strovas, Tim J., Joe M. Dragavon, Tyler J. Hankins, James B. Callis, Lloyd W. Burgess, and Mary E. Lidstrom. "Measurement of Respiration Rates of Methylobacterium extorquens AM1 Cultures by Use of a Phosphorescence-Based Sensor." Applied and Environmental Microbiology 72, no. 2 (February 2006): 1692–95. http://dx.doi.org/10.1128/aem.72.2.1692-1695.2006.

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ABSTRACT Respiration rates of bacterial cultures can be a powerful tool in gauging the effects of genetic manipulation and environmental changes affecting overall metabolism. We present an optical method for measuring respiration rates using a robust phosphorescence lifetime-based sensor and off-the-shelf technology. This method was tested with the facultative methylotroph Methylobacterium extorquens AM1 to demonstrate subtle mutant phenotypes.

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47

Pranowo, Harno Dwi, Iqmal Tahir, and Ajidarma Widiatmoko. "QUANTITATIVE RELATIONSHIP OF ELECTRONIC STRUCTURE AND INHIBITION ACTIVITY OF CURCUMIN ANALOGS ON ETHOXYRESORUFIN o-DEALKYLATION (EROD) REACTION." Indonesian Journal of Chemistry 7, no. 1 (June 15, 2010): 78–82. http://dx.doi.org/10.22146/ijc.21717.

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Electronic structure and inhibition activity relationship study of curcumin analogs has been established for 29 curcumin analogs on Ethoxyresorufin O-Dealkylation (EROD) reaction using atomic net charge descriptor based on AM1 semiempirical calculations. The QSAR (Quantitative Structure and Activities Relationships) equation model was determined by statistical parameter from multiple regression analysis and leave-one-out cross validation method. The best QSAR equation was described: Keywords: curcumin, QSAR, descriptor, atomic net charge, semiempirical methods.

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48

Al-amiri, Allaa Hussein Mhdi Salh. "Diagnosis of Active Groups of Samples Taken (Aniline-Benzoic Acid -Acetic Anhydride and Comparing: The Results of the Laboratory)." International Journal of Chemistry 8, no. 2 (April 15, 2016): 51. http://dx.doi.org/10.5539/ijc.v8n2p51.

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<p><em>FTIR comparison study</em> between experimental and computational calculations by four molecular modeling methods (AM1, PM3, HF and DFT) was carried out to identify the vibration frequencies of different bonds for some compounds such as benzoic acid, aniline and phthalic anhydride to evaluate the accuracy of each method and to determine the shift value of frequencies for each bond. Results obtained confirm that the accuracy depends on the type of method and the functional group present near the certain bond. </p>

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49

Luque, F. J., M. Bachs, and Modesto Orozco. "An optimized AM1/MST method for the MST-SCRF representation of solvated systems." Journal of Computational Chemistry 15, no. 8 (August 1994): 847–57. http://dx.doi.org/10.1002/jcc.540150806.

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Jakalian, Araz, Bruce L. Bush, David B. Jack, and Christopher I. Bayly. "Fast, efficient generation of high-quality atomic charges. AM1-BCC model: I. Method." Journal of Computational Chemistry 21, no. 2 (January 30, 2000): 132–46. http://dx.doi.org/10.1002/(sici)1096-987x(20000130)21:2<132::aid-jcc5>3.0.co;2-p.

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