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Journal articles on the topic 'Hückel molecular orbital theory'

Author: Grafiati

Published: 6 September 2023

Last updated: 25 July 2025

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1

MORALES-BAYUELO, ALEJANDRO, JUAN TORRES, and RICARDO VIVAS-REYES. "HÜCKEL TREATMENT OF PYRROLE AND PENTALENE AS A FUNCTION OF CYCLOPENTADIENYL USING LOCAL QUANTUM SIMILARITY INDEX (LQSI) AND THE TOPO-GEOMETRICAL SUPERPOSITION APPROACH (TGSA)." Journal of Theoretical and Computational Chemistry 11, no. 01 (2012): 223–39. http://dx.doi.org/10.1142/s0219633612500150.

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In this paper some of the characteristic of Hückel method, were exploited in order to obtain some important results, through a new technique with which it is possible to obtain non-degenerate characteristic values as in the case of pyrrole and allowing the expression of conjugated ring systems (Pentalene) as function of a system of diene monomer (Cyclopentadienyl). The local similarity index based on the Hirshfeld partitioning in the framework of conceptual Density Functional Theory (DFT), was introduced in the secular determinant of the Hückel method and was applied to Pyrrole molecule in ord

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2

Wolfe, Saul, Zheng Shi, C. E. Brion, et al. "Electron momentum spectroscopy of the frontier electrons of DABCO does not support an sp3 hybrid lone-pair description." Canadian Journal of Chemistry 80, no. 3 (2002): 222–27. http://dx.doi.org/10.1139/v01-201.

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The highest occupied molecular orbital (HOMO) and next-highest occupied molecular orbital (NHOMO) valence orbital electron density distributions of 1,4-diazabicyclo[2.2.2]octane (DABCO) have been investigated by electron momentum spectroscopy, a technique that probes the orbital-like nature of valence (frontier) electron transfer out of a molecule. The experimental results are compared to a range of 6-311++G** calculations to assess the relative merits of three different orbital models that have commonly been used in chemistry. The delocalized (correlated) canonical KohnSham orbitals calculat

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3

Grado-Caffaro, M. A., and M. Grado-Caffaro. "A Molecular-Orbital Model for Amorphous Group IV Semiconductors." Active and Passive Electronic Components 20, no. 1 (1997): 41–44. http://dx.doi.org/10.1155/1997/65485.

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A theoretical model based on standard molecular-orbital theory and extended Hückel approach is proposed. This model is valid for amorphous group IV semiconductors and represents a substantial improvement of the state of the art.

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4

Langler, Richard Francis, та Laura Precedo. "On the possibilities of π-ylides". Canadian Journal of Chemistry 68, № 6 (1990): 939–41. http://dx.doi.org/10.1139/v90-146.

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A systematic survey of substituted annulenes, using zeroth order Hückel theory, has uncovered a subclass of such structures which are predicted to have very substantial charge separation. An examination of selected structures by MNDO semi-empirical molecular orbital computations provided support for the Hückel descriptions. Such compounds may be of immediate interest to those pursuing synthetic or mechanistic problems which involve cycloaddition reactions. Keywords: π-ylides.

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5

Sharma, Brahama D. "Molecular Orbital (Hückel) Theory and Linus Pauling: A Historical Perspective." Journal of Chemical Education 73, no. 8 (1996): 746. http://dx.doi.org/10.1021/ed073p746.

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6

Rashed, Effat A. "Calculations of Constant-Height STM Images of Fullerene C60 Adsorbed onto a Surface." Journal of Spectroscopy 2023 (June 21, 2023): 1–7. http://dx.doi.org/10.1155/2023/8841630.

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Constant-height scanning tunneling microscopy (STM) images of a C60 molecule adsorbed onto a surface were calculated using symmetry-adapted Hückel molecular orbitals (HMOs). Three adsorption orientations of C60 are considered. The interaction between the C60 molecule and the surface was treated using symmetry arguments only. Projection operators were used to generate symmetry-adapted HMOs of the molecule. These orbitals were then used to construct idealized constant-height STM images using the simple tunneling theory of Tersoff and Hamann. A comparison is made with published experimental STM m

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7

Teschmit, Grit, P. Strauch, A. Barthel, J. Reinhold, and R. Kirmse. "EPR-Einkristall-Untersuchungen an (n-Bu4N)2[Cu(dmit)2] im antiferromagnetisch gekoppelten Wirtsgitter (n-Bu4N)2[(dmit)Cu(tto)Cu(dmit)]: Ein Beitrag zur Aufklärung der sogenannten „paramagnetischen Verunreinigung“ im Wirtsgitter / A Single Crystal EPR Investigation on (n-Bu4N)2[Cu(dmit)2] in the Antiferromagnetically Coupled Host Lattice (n-Bu4N)2[(dmit)Cu(tto)Cu(dmit)]: A Contribution to the Nature of the So-called “Paramagnetic Impurities”." Zeitschrift für Naturforschung B 54, no. 7 (1999): 832–38. http://dx.doi.org/10.1515/znb-1999-0702.

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Single-crystal EPR investigations on the paramagnetic CuII impurity present in the binuclear antiferromagnetically coupled complex (n-Bu4N)2[(dmit)CuII(tto)CuII,(dmit)] (dmit = dimercaptoisotrithion, tto = tetrathiooxalate) identify the mononuclear S =½ complex [CuII(dmit)2]2− as being responsible for the observed EPR spectra. The 63Cu hyperfine structure data as well as the data obtained from density functional theory (DFT) and extended Hückel theory molecular orbital (EHT-MO) calculations were used to characterize the spin-density distribution of the copper complex.

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8

Dumont, Randall S. "Effects of charging and polarization on molecular conduction via the source-sink potential method." Canadian Journal of Chemistry 92, no. 2 (2014): 100–111. http://dx.doi.org/10.1139/cjc-2013-0227.

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The current−voltage relationships of butadiene and octatetraene are computed using the source-sink potential method with self-consistent Hückel theory. Molecular orbital resonances appear as steps in current, considerably broader than the resonances in the transmission spectrum at any specific bias. This broadening is due primarily to the charging of the molecule as bias increases. A perturbation theory based model is derived to account for the observations. In the case of octatetraene, the HOMO resonance manifests at high voltage when the HOMO energy is raised to the Fermi level of the plus e

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9

Chauvin, Remi, Christine Lepetit, Valérie Maraval, and Léo Leroyer. "Variation of aromaticity by twisting or expanding the ring content." Pure and Applied Chemistry 82, no. 4 (2010): 769–800. http://dx.doi.org/10.1351/pac-con-09-11-07.

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Generalization of the Hückel rule predicts that the (anti)aromaticity of a neutral ring is qualitatively reverted upon a single twist of the π-orbital array (Möbius interconversion), and is preserved upon expansion of all the bonds by single C2 units (ring carbo-merization). These opposite effects are addressed from quantitative theoretical and experimental standpoints, respectively. (i) According to most resonance energy (RE) schemes, the RE value of a Möbius ring is not the opposite of that of the Hückel version. This also applies to the Aihara’s and Trinajstic’s topological resonance energy

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10

Litofsky, Joshua, and Rama Viswanathan. "Introduction to Computational Chemistry: Teaching Hückel Molecular Orbital Theory Using an Excel Workbook for Matrix Diagonalization." Journal of Chemical Education 92, no. 2 (2014): 291–95. http://dx.doi.org/10.1021/ed500376q.

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11

Mantela, Marilena, Constantinos Simserides, and Rosa Di Felice. "LCAO Electronic Structure of Nucleic Acid Bases and Other Heterocycles and Transfer Integrals in B-DNA, Including Structural Variability." Materials 14, no. 17 (2021): 4930. http://dx.doi.org/10.3390/ma14174930.

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To describe the molecular electronic structure of nucleic acid bases and other heterocycles, we employ the Linear Combination of Atomic Orbitals (LCAO) method, considering the molecular wave function as a linear combination of all valence orbitals, i.e., 2s, 2px, 2py, 2pz orbitals for C, N, and O atoms and 1s orbital for H atoms. Regarding the diagonal matrix elements (also known as on-site energies), we introduce a novel parameterization. For the non-diagonal matrix elements referring to neighboring atoms, we employ the Slater–Koster two-center interaction transfer integrals. We use Harrison-

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12

LETELIER, JORGE RICARDO. "VIBRONIC EXTENDED HÜCKEL THEORY AND THE FORCES IN MOLECULES." International Journal of Modern Physics C 10, no. 07 (1999): 1177–92. http://dx.doi.org/10.1142/s0129183199000966.

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A method is presented that allows the computation of the forces acting on the atoms in a molecule along each of the symmetry nuclear displacements coordinates. The method works within the Extended Hückel formalism and makes use of the standard output of a charge-iterated calculation. In this work, examples are given of the different contributions to the total force, arising from the populated molecular orbitals, that act on the atoms in several diatomic molecules and the shape of the vibrational potential is analyzed. Also, the distortions (Peierls) that take place in a linear triatomic system

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13

Aragoni, M. Carla, Massimiliano Arca, Francesco A. Devillanova, et al. "An experimental and theoretical approach to phosphonodithioato complexes: molecular orbital analysis by hybrid-DFT and EHT calculations on trans-bis[O-alkyl-phenylphosphonodithioato]NiII, and vibrational assignments." Canadian Journal of Chemistry 79, no. 10 (2001): 1483–91. http://dx.doi.org/10.1139/v01-163.

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The synthesis and the full spectroscopic characterization (FT-IR, FT-Raman, 31P CP MAS NMR) of trans-bis[O-ethyl-phenylphosphonodithioato]NiII (3) are reported. On the basis of hybrid-Density Functional Theory (DFT) calculations and Extended Hückel Theory (EHT) calculations, performed on the simpler trans-bis[O-methyl-phenyl phos phono dithioato]NiII (2) model complex, the electronic structures of phosphonodithioato complexes in their ground states are fully described, and in particular the vibrational features are deeply analyzed, allowing an unprecedented insight into the vibrational feature

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14

WANG, Dan. "Application of Simplified Hückel Molecular Orbital Theory to Judge the Geometric Configuration of H₄ and Its Molecular Ions." University Chemistry 33, no. 3 (2018): 84–86. http://dx.doi.org/10.3866/pku.dxhx201711020.

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15

TO, TRAN THINH, and STEFAN ADAMS. "CHARGE TRANSPORT AND LIGHT ABSORPTION IN CONJUGATED SYSTEMS FROM EXTENDED HÜCKEL METHOD AND MARCUS THEORY." International Journal of Computational Materials Science and Engineering 01, no. 02 (2012): 1250020. http://dx.doi.org/10.1142/s2047684112500200.

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A simple first principle model was developed based on extended Hückel-type orbital calculation, Marcus electron transport theory and two-dimensional-electron-gas model for the treatment of charge transport in conjugated polymers. Though simple and easy to compute, the effect of the applied electric-field is factored in. Based on this, a complete one-dimensional device model with a single layer of conjugated polymer sandwiched between two electrodes was developed with poly(3-hexylthiophene) (P3HT) as a case study. Simulated J-V curves show that π-π charge transport is much more pronounced than

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16

COLLADO, J. R. ALVAREZ. "ON THE DIAGONALIZATION OF HERMITIAN MATRICES, AND ITS USE TO CALCULATE THE HÜCKEL ELECTRONIC STRUCTURE OF LARGE CARBON NANOTUBES." Journal of Theoretical and Computational Chemistry 06, no. 03 (2007): 477–85. http://dx.doi.org/10.1142/s0219633607003106.

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In this paper, a method for calculating all the Hückel molecular orbitals (MO) of large (16.000 atoms) carbon zigzag nanotubes is presented. These MO have been obtained by combining the singular value decomposition (SVD), the Sylvester–Hadamard transform, and the theory of Hamiltonian–Symplectic matrices. Numerical diagonalization of hermitian matrices is reviewed and improved. A new, more advantageous, (tri-diagonal) algorithm is proposed and analyzed. The reactivity of the atoms is described by calculating their free valence indices.

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17

Yew, Yun Ru, and Nor Haniza Sarmin. "The Minimum Degree Energy of the Cayley Graph Associated to the Dihedral Group of Order Six with Subsets of Order Two and Three." Malaysian Journal of Fundamental and Applied Sciences 21, no. 2 (2025): 1936–44. https://doi.org/10.11113/mjfas.v21n2.3932.

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The energy of a simple graph in graph theory is defined as the sum of the absolute values of the eigenvalues of the graph's adjacency matrix, a concept inspired by Hückel Molecular Orbital theory. Chemists originally used this idea to estimate the energy associated with π-electron orbitals in conjugated hydrocarbons. The minimum degree energy, on the other hand, is defined as the sum of the absolute values of the eigenvalues of the graph's minimum degree matrix. A Cayley graph associated to a finite group with a subset is defined as a graph in which the vertices are the elements of the group a

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18

Sherman, Douglas Franklyn, Daniel Dilella, and Kenneth J. Miller. "Partitioning of molecular systems and subsystem replacement by single-centered perturbations: II. Applications of the pseudo substituent technique within hückel molecular orbital theory." International Journal of Quantum Chemistry 8, S8 (2009): 187–99. http://dx.doi.org/10.1002/qua.560080823.

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19

Nagaoka, Shin-ichi, Tatsunobu Kokubo, Hiroyuki Teramae, and Umpei Nagashima. "Practical Training in Simple Hückel Theory: Matrix Diagonalization for Highly Symmetric Molecules and Visualization of Molecular Orbitals." Journal of Chemical Education 95, no. 9 (2018): 1579–86. http://dx.doi.org/10.1021/acs.jchemed.8b00244.

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20

Nagaoka, Shin-ichi, Yoshinori Yamasaki, Hiroyuki Teramae, Umpei Nagashima, and Tatsunobu Kokubo. "Addition to “Practical Training in Simple Hückel Theory: Matrix Diagonalization via Tridiagonalization, Cyclobutadiene, and Visualization of Molecular Orbitals”." Journal of Chemical Education 97, no. 8 (2020): 2373–74. http://dx.doi.org/10.1021/acs.jchemed.0c00857.

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21

Ramakrishnan, Raghunathan. "A Simple Hückel Molecular Orbital Plotter." Journal of Chemical Education 90, no. 1 (2012): 132–33. http://dx.doi.org/10.1021/ed300085g.

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22

Liu, Yue, Ying Liu, and Michael G. B. Drew. "Correlation between Fourier series expansion and Hückel orbital theory." Journal of Mathematical Chemistry 51, no. 2 (2012): 503–31. http://dx.doi.org/10.1007/s10910-012-0092-9.

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23

Gutman, I., Y. Hou, H. B. Walikar, H. S. Ramane, and P. R. Hampiholi. "No Hückel graph is hyperenergetic." Journal of the Serbian Chemical Society 65, no. 11 (2000): 799–801. http://dx.doi.org/10.2298/jsc0011799g.

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If G is a molecular graph with n vertices and if ?1, ?2, ..., ?n are its eigenvalues, then the energy of G is equal to E(G) = |?1| + |?2|+ ... + |?n|. If E(G) > 2n - 2, then G is said to be hyperenergetic. We show that no H?ckel graph (= the graph representation of a conjugated hydrocarbon within the H?ckel molecular orbital model) is hyperenergetic.

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24

Zahedi, Mansour, and Mohammed Al-Kobaisi (Latif). "Resonance Stabilization Study of Some Fullerenes Cn(20 ≤ n ≤ 88): Is n = 32 a ‘Magic’ Number?" Journal of Chemical Research 23, no. 1 (1999): 52–53. http://dx.doi.org/10.1177/174751989902300132.

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A π-orbital axis vector (POAV) analysis used in Hückel molecular orbital approximation calculations indicates that the cutoff in the fullerene mass spectrum at C n ( n = 32) must naturally occur with no need to define a ‘magic’ number.

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25

Gutman, Ivan. "Hückel Molecular Orbital Energies and Bond Orders of Cyclacenes." Polycyclic Aromatic Compounds 8, no. 4 (1996): 251–57. http://dx.doi.org/10.1080/10406639608048352.

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26

Rousseau, R., R. Aroca, and M. L. Rodríguez-Méndez. "Extended Hückel molecular orbital model for lanthanide bisphthalocyanine complexes." Journal of Molecular Structure 356, no. 1 (1995): 49–62. http://dx.doi.org/10.1016/0022-2860(95)08905-b.

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27

Slee, Tom S., and Preston J. MacDougall. "The correspondence between Hückel theory and ab initio atomic charges in allyl ions." Canadian Journal of Chemistry 66, no. 11 (1988): 2961–62. http://dx.doi.org/10.1139/v88-459.

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Atomic charges for the allyl cation and anion are reported, as defined by the quantum theory of atoms in molecules. An interesting feature of these charges is that they differ considerably from expectations based on simple π orbital models. The reasons for the difference are investigated and it is shown that the charges are both compatible with and understandable in terms of simple orbital models.

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28

Hudson, R. F. "The Extended-Hückel perturbation theory and the concept of orbital balance." Journal of Molecular Structure: THEOCHEM 261 (July 1992): 91–112. http://dx.doi.org/10.1016/0166-1280(92)87068-b.

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29

Dias, Jerry Ray. "Valence-Bond and Hückel Molecular Orbital Diradicals—Alternant versus Nonalternant Effects." Australian Journal of Chemistry 56, no. 12 (2003): 1225. http://dx.doi.org/10.1071/ch02221.

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Two distinct classes of diradicals are examined and compared. Valence-bond diradicals are topologically enforced, whereas Hückel molecular orbital diradicals can undergo skeletal distortions and transform to a nonradical form and tend to gain or lose electrons to form stable polyions. Alternant hydrocarbon diradicals are nonpolar species and nonalternant hydrocarbon diradicals tend to be polar species and less prevalent.

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30

Matito, Eduard, Ferran Feixas, and Miquel Solà. "Electron delocalization and aromaticity measures within the Hückel molecular orbital method." Journal of Molecular Structure: THEOCHEM 811, no. 1-3 (2007): 3–11. http://dx.doi.org/10.1016/j.theochem.2007.01.015.

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31

Dias, Jerry Ray. "Facile construction of polyene molecules with high hückel molecular orbital degeneracy." Tetrahedron Letters 32, no. 36 (1991): 4659–60. http://dx.doi.org/10.1016/s0040-4039(00)92274-3.

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32

Wissner, Allan. "HMO Version 1.1: A Hückel molecular orbital program for the Macintosh." Tetrahedron Computer Methodology 3, no. 2 (1990): 63–71. http://dx.doi.org/10.1016/0898-5529(90)90109-l.

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33

KENNEDY, R. V., and J. E. ALLEN. "The floating potential of spherical probes and dust grains. II: Orbital motion theory." Journal of Plasma Physics 69, no. 6 (2003): 485–506. http://dx.doi.org/10.1017/s0022377803002265.

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Probe theory is generally used to find the potential of dust particles immersed in plasma. The orbital motion limited theory (OML) is often used to find the potential at the probe surface, but the assumptions underlying this theory are usually not valid in the case of dust and the more general orbital motion (OM) theory is much harder to calculate. Solutions are given for the OM theory in a range of cases applicable to dust. It is shown that the surface potential the full theory gives reduces to the OML result for small probes. Commonly in dusty plasmas the OML surface potential is used, with

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34

Trinajstić, Nenad. "New developments in Hückel theory." International Journal of Quantum Chemistry 12, S11 (2009): 469–77. http://dx.doi.org/10.1002/qua.560120854.

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35

Peric, Miljenko, Ivan Gutman та Jelena Radic-Peric. "The Hückel total π-electron energy puzzle". Journal of the Serbian Chemical Society 71, № 7 (2006): 771–83. http://dx.doi.org/10.2298/jsc0607771p.

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In spite of being based on drastic simplifications, the H?ckel molecular orbital (HMO) quantum-mechanical model provides a reasonably good description of the properties of ?-electrons in conjugated molecules. The HMO approach is found to be particularly successful in the case of the total ?-electron energy (E), by means of which it is possible to calculate enthalpies of formation and similar thermodynamic characteristics of conjugated compounds. In this paper it is shown that expressions equivalent to E can be deduced within much more accurate quantum mechanical considerations. This might expl

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36

Dowd, Paul. "Unusual hückel molecular orbital degeneracy or some non-alternant, no-kekulé molecules." Tetrahedron Letters 32, no. 4 (1991): 445–46. http://dx.doi.org/10.1016/s0040-4039(00)79463-9.

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37

Radhakrishnan, T. P. "Ground state spin of some molecules with unusual hückel molecular orbital degeneracy." Tetrahedron Letters 32, no. 35 (1991): 4601–2. http://dx.doi.org/10.1016/0040-4039(91)80050-g.

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38

Zhao, Ming, and Benjamin M. Gimarc. "Three-dimensional Hückel molecular orbital energy level correlation diagrams for polyhedral rearrangements." Polyhedron 14, no. 10 (1995): 1315–25. http://dx.doi.org/10.1016/0277-5387(94)00407-6.

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39

Dias, Jerry Ray. "Facile calculation of Hückel molecular orbital eigenvalues of short (n,0) nanotubes." Chemical Physics Letters 647 (March 2016): 79–84. http://dx.doi.org/10.1016/j.cplett.2016.01.055.

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40

Krivul’ko, K. F., and A. P. Klishchenko. "Taking into account universal intermolecular interactions by the Hückel molecular orbital method." Journal of Applied Spectroscopy 73, no. 5 (2006): 748–52. http://dx.doi.org/10.1007/s10812-006-0149-2.

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41

Zeyrek, C. Tugrul. "Importance of Orbital Complementarity in Spin Coupling through Two Different Bridging Groups in Dicopper(II) Complexes of Endogenous Alkoxo Bridging Ligand with Exogenous Carboxylate: Ab-initio and Semi-Empirical Calculations." Zeitschrift für Naturforschung A 62, no. 7-8 (2007): 409–16. http://dx.doi.org/10.1515/zna-2007-7-810.

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The influence of overlap interactions between the bridging ligands and the metal d orbitals on the super-exchange coupling constant are studied by means of ab-initio restricted Hartree-Fock molecular orbital calculations. The interaction between the magnetic d orbitals and the HOMOs of the carboxylate oxygen atoms are investigated in homologous asymmetrically dibridged dicopper(II) complexes which have significantly different - 2J values (the energy separation between the spin-triplet and spin-singlet states). In order to determine the nature of the fronter orbitals, extended Hückel molecular

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42

Baum, James Clayton, Eric Donald Martin, Jack Leon Ginsburg, and Richard Francis Langler. "Anticipating molecular polarity 1: a back-of-the-envelope approach to topologically induced polarity in non-alternant monocycles." Canadian Journal of Chemistry 73, no. 10 (1995): 1719–26. http://dx.doi.org/10.1139/v95-210.

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Perturbation theory is applied to fully π-bonded non-alternant monocycles at the Hückel level. An effective "back-of-the-envelope" approach is developed that permits one to anticipate Hückel charge patterns for these monocycles. Very little modification is required to alter the basic approach so that it will permit rapid anticipation of AM1 -calculated charge patterns for such compounds. Keywords: hydrocarbon polarity, perturbation theory.

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43

Galvão, Adelino M., and João L. Ferreira da Silva. "Analysis of 1H NMR Data for Arene-Metal Complexes Using Extended Huckel Calculations." Collection of Czechoslovak Chemical Communications 63, no. 3 (1998): 299–304. http://dx.doi.org/10.1135/cccc19980299.

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This work reports the use of extended Hückel molecular orbital (EHMO) calculations to correlate pz electronic densities of aromatic carbons in group VI metal-bis(η6-arene) complexes with the respective 1H NMR chemical shifts. The effect of delocalization on the acceptor properties and stabilization of ligand orbitals is analyzed comparing complexes of naphthalene, biphenyle and fluorene.

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44

Gill, Wendy R., Marion E. Jones, Kenneth Wade, William W. Porterfield, and Edward H. Wong. "Stability patterns in borane cluster chemistry rationalised by extended Hückel molecular orbital studies." Journal of Molecular Structure: THEOCHEM 261 (July 1992): 161–74. http://dx.doi.org/10.1016/0166-1280(92)87074-a.

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45

Wang, Xiang-Yang. "Orbital binding effect in molecular orbital theory." International Journal of Quantum Chemistry 50, no. 3 (1994): 197–205. http://dx.doi.org/10.1002/qua.560500305.

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46

Harvey, Pierre D., Peter Johnston та Neil J. Coville. "Electron inductive perturbation(s) of heteronuclear metal–metal bonds. Isocyanide and indenyl derivatives of the mixed metal dimers [(η5–C5H5)Fe(CO)2Re(CO)5] and [MnRe(CO)10]". Canadian Journal of Chemistry 72, № 10 (1994): 2176–82. http://dx.doi.org/10.1139/v94-276.

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The properties of the heteronuclear metal–metal bonds in the unbridged [η5–C5H5)Fe(CO)2Re(CO)5−n(CNR)n] and [(η5–C9H7)Fe(CO)2Re(CO)5−n(CNR)n complexes (n = 0, 1, 2; R = tert-butyl (tBu) and 2,6-dimethylphenyl (Xy)) and the two equatorially substituted isomers of [MnRe(CO)8(CN-tBu)2] have been investigated theoretically by Extended Hückel Molecular Orbital calculations (EHMO) and experimentally by UV–visible spectroscopy, electrochemistry, and by microRaman or FT-Raman spectroscopy. The expected dσ* orbital is the lowest unoccupied molecular orbital (LUMO), mainly fabricated by interactions of

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47

Rodríguez, Leonardo J., and Fernando Ruette. "Semiempirical molecular orbital theory." Journal of Molecular Structure: THEOCHEM 287 (November 1993): 179–84. http://dx.doi.org/10.1016/0166-1280(93)87220-8.

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48

ERKOÇ, ŞAKIR. "STRUCTURAL AND ELECTRONIC PROPERTIES OF CARBON NANOTUBES." International Journal of Modern Physics C 11, no. 01 (2000): 175–82. http://dx.doi.org/10.1142/s0129183100000158.

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The structural and electronic properties of optimized open-ended single-wall carbon nanotubes with zigzag geometry have been investigated. The calculations were performed using molecular mechanics, extended Hückel, and AM1–RHF semiempirical molecular orbital methods. It has been found that the density of states of the zigzag model is sensitive to the tube size and changes as the tube length increases. On the other hand the energetics of the tube shows an almost linear dependence to the tube length, and a converging characteristics with respect to the number of hexagons forming the tube.

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Cramer, Janice A., Michael J. McGlinchey, and Jean-Yves Saillard. "Structural features of (C5H5)2Mo2S6 clusters: an EHMO study." Canadian Journal of Chemistry 67, no. 11 (1989): 1931–35. http://dx.doi.org/10.1139/v89-300.

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Extended Hückel molecular orbital calculations on S6 in the planar D6h configuration and in the bent C2v geometry reveal that the former is favored for S62+ and the latter for S64−. It is shown that the additional six electrons would populate one π* and two σ* orbitals in the planar structure. In contrast, when these hexasulfur fragments are incorporated in triple-decker sandwich compounds the pseudo-D6h structure is favored for [(C5H5)Mo(S6)Mo(C5H5)]6+ but the C2v geometry is predicted for [(C5H5)Mo(S6)Mo(C5H5)]2+ which possesses only four more electrons. The required extra two electrons are

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Huang, Yuan Ming, and Bao Gai Zhai. "Purple Photoluminescence from Banana-Shaped Molecules 1,3-Phenylene bis(4-methoxybenzylideneamine)." Key Engineering Materials 428-429 (January 2010): 182–85. http://dx.doi.org/10.4028/www.scientific.net/kem.428-429.182.

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The optical absorption and photoluminescence spectra of banana-shaped molecules 1,3-phenylene bis(4-methoxybenzylideneamine) have been investigated with an ultraviolet-visible spectrometers and a spectrofluorometer, respectively. The optical characterizations indicate that the banana-shaped molecules exhibit strong absorptions in a broad range of 260-370 nm and that they can give off strong purple photoluminescence when excited by ultraviolet photons. Using Hückel tight-binding program, we have calculated the electronic structures of the banana-shaped molecules. In light of the calculated elec

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