Molecular orbitals from group orbitals. I. A perturbational molecular orbital treatment of the electronic structures, shapes and conformations of AHmBHn Systems

1976 ◽  
Vol 54 (6) ◽  
pp. 949-962 ◽  
Author(s):  
Myung-Hwan Whangbo ◽  
Saul Wolfe
Keyword(s):  
Molecular Orbital ◽  
Electronic Structures ◽  
Molecular Orbitals ◽  
Orbital Interaction ◽  
Molecular Systems ◽  
Group Orbitals

A procedure is proposed which allows the group orbitals of a fragment AHm—to be obtained from the molecular orbitals of the molecule AHm—H. Orbital interaction diagrams constructed from these group orbitals have been found useful in the description of the electronic structures and conformations of a variety of molecular systems of the type AHmBHn. The molecules that have been treated by this procedure include ethane, hydrazine, diphosphine, aminophosphine, aminoborane, and sulfonium and phosphonium ylids.

The molecular orbital theory of chemical valency. III. Properties of molecular orbitals

1950 ◽  
Vol 202 (1069) ◽  
pp. 155-165 ◽  
Keyword(s):  
Perturbation Theory ◽  
Molecular Orbital ◽  
Molecular Orbitals ◽  
Molecular Properties ◽  
The Other ◽  
Molecular Orbital Theory ◽  
Special Significance ◽  
Orbital Theory ◽  
Molecular Systems ◽  
Normal States

The discussion of molecular orbitals and equivalent orbitals, given in previous papers, is carried a stage further. It is shown that certain molecular properties can be evaluated using either equivalent or molecular orbitals. On the other hand, a study of the changes produced by ionization demonstrates that molecular orbitals have a special significance and that certain energy parameters associated with them are closely related to ionization potentials. For the purpose of this discussion a perturbation theory is developed to deal with the changes produced in molecular systems when disturbed from their normal states.

Molecular orbitals from group orbitals. II Conformational analysis of Systems with three heavy atoms. The XCH2CH2 system and the anomeric effect

1976 ◽  
Vol 54 (6) ◽  
pp. 963-968 ◽  
Author(s):  
Myung-Hwan Whangbo ◽  
Saul Wolfe
Keyword(s):  
Conformational Analysis ◽  
Molecular Orbital ◽  
Molecular Orbitals ◽  
Explicit Calculation ◽  
Anomeric Effect ◽  
Relative Level ◽  
Heavy Atoms ◽  
Carbonium Ions ◽  
Group Orbitals ◽  
Nodal Properties

A procedure for the conformational analysis of Systems of the type AHmBHnDHk is proposed, in terms of interactions between AHmBHn— and —DHk fragments. The nodal properties and relative level orderings of the group orbitals of these fragments are obtained from the molecular orbitals of the molecules AHmBHn+1 and DHk+1. Attention is focussed upon two-orbital two-electron stabilizing and two-orbital four-electron destabilizing interactions between these fragments. A consistent interpretation of the conformational behaviour of n-propyl and 2-fluoroethyl carbonium ions and carbanions is attempted within the framework of this group molecular orbital procedure. The conformational behaviour of FCH2OH, a model for the anomeric effect, has also been examined. It is shown that the group molecular orbital approach accommodates two earlier interpretations of the anomeric effect, one of which focusses upon bond–bond interactions; the second focusses upon effects of the oxygen lone pairs. Some limitations of the model are noted, in particular the problem associated with explicit calculation of the magnitudes of different stabilizing and destabilizing interactions.

scholarly journals Electronic Properties of Triangle Molybdenum Disulfide (MoS2) Clusters with Different Sizes and Edges

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1157
Author(s):  
Songsong Wang ◽  
Changliang Han ◽  
Liuqi Ye ◽  
Guiling Zhang ◽  
Yangyang Hu ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Electronic Properties ◽  
Absorption Spectra ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Edge States ◽  
Frontier Orbitals ◽  
Edge Structure ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The electronic structures and transition properties of three types of triangle MoS2 clusters, A (Mo edge passivated with two S atoms), B (Mo edge passivated with one S atom), and C (S edge) have been explored using quantum chemistry methods. The highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap of B and C is larger than that of A, due to the absence of the dangling of edge S atoms. The frontier orbitals (FMOs) of A can be divided into two categories, edge states from S3p at the edge and hybrid states of Mo4d and S3p covering the whole cluster. Due to edge/corner states appearing in the FMOs of triangle MoS2 clusters, their absorption spectra show unique characteristics along with the edge structure and size.

The effect of ionic lattices on the electronic structures of polyatomic ions. I. The triiodide ion

1966 ◽  
Vol 19 (9) ◽  
pp. 1567 ◽  
Author(s):  
RD Brown ◽  
EK Nunn
Keyword(s):  
Electronic Structure ◽  
Molecular Orbital ◽  
Electron Energy ◽  
Electronic Structures ◽  
Valence Electron ◽  
Bond Orders ◽  
Bond Lengths ◽  
Molecular Orbital Study ◽  
Crystalline Environment ◽  
Asymmetric Stretch

A VESCF molecular-orbital study of the electronic structure of the triiodide anion in its crystalline environment in caesium triiodide and in tetraphenylarsonium triiodide reveals the effect of the lattices upon the electronic structures. The calculated total valence-electron energy as a function of the position of the central iodine nucleus provides an understanding of the observed geometries of the anion in the two crystals. The energy plot also implies that the asymmetric stretch of the triiodide is strongly anharmonic in the crystal. A satisfactory correlation exists between observed iodine : iodine bond lengths and computed bond orders.

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