Energetics of the singlet and triplet states of alkylnitrenium ions: ab initio molecular orbital calculations

1989 ◽  
Vol 111 (11) ◽  
pp. 3987-3996 ◽  
Author(s):  
George P. Ford ◽  
P. S. Herman
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Triplet States ◽  
Singlet And Triplet States

Singlet and Triplet States of Aminonitrenes: An Ab Initio Molecular Orbital Study

1973 ◽  
Vol 51 (20) ◽  
pp. 3303-3308 ◽  
Author(s):  
N. C. Baird ◽  
R. F. Barr
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Triplet States ◽  
Density Distributions ◽  
Molecular Orbital Study ◽  
Triplet Splitting ◽  
Optimum Geometry ◽  
Singlet And Triplet States ◽  
Carbonyl Substitution

Ab initio STO-3G molecular orbital calculations are reported for the lowest singlet and the lowest triplet state of the aminonitrenes H2NN, CH3(H)NN, F(H)NN, and HCO(H)NN. The optimum geometry calculated for the H2NN triplet is nonplanar (Cs symmetry), with N—N and N—H bond distances of 1.436 and 1.034 Å, and HNN and HNH angles both of 107.5°. The optimum singlet is predicted to be planar (C2v symmetry), with N—N and N—H distances of 1.276 and 1.041 Å respectively, and an HNN angle of 124°. An analysis of the calculated geometries and electron density distributions indicates that the "idealized" representations 3 and 5 are adequate to explain the bonding in the triplet and singlet respectively. The effects of methyl, fluoro, and carbonyl substitution upon the singlet–triplet splitting and upon the charge distribution are discussed. The optimum-geometry triplet is predicted to be slightly more stable than the optimum-geometry singlet in all cases.

A pairwise additivity scheme for conformational energies of substituted ethanes

1975 ◽  
Vol 343 (1632) ◽  
pp. 1-10 ◽  
Keyword(s):  
Large Deviations ◽  
Ab Initio ◽  
Dihedral Angle ◽  
Molecular Orbital ◽  
Methyl Groups ◽  
Molecular Orbital Calculations ◽  
Linear Combinations ◽  
Strongly Interacting ◽  
Conformational Energies

Ab initio molecular orbital calculations are used to explore additivity in the conformational energies of poly-substituted ethanes in terms of conformational energies of ethane and appropriate mono- and 1,2-di-substituted derivatives. Such relations would allow complex calculations for poly-substituted ethanes to be replaced by much simpler ones on a small number of parent molecules. General expressions for the linear combinations are derived from the assumption that interactions between vicinal substituents are pairwise additive and depend only on the vicinal dihedral angle. The additivity scheme is tested for 15 ethanes, di-, tri- or tetrasubstituted by cyano and methyl groups and for a smaller number of fluoroethanes. Additivity applies to within 0.1- 0.3 k J mol -1 in the methylethanes and mostly to within about 0.7- 0.8 kJ mol -1 in cyanoethanes. Large deviations are found among the geminally substituted fluoroethanes. It is suggested that the additivity approximation is most successful in the absence of strongly interacting geminal groups. Predictions are made of conformational energies of ten hexa(cyano- and methyl-) substituted ethanes.

Gas-Phase Tautomerism in the Triazoles and Tetrazoles: A Study by Photoelectron Spectroscopy and ab Initio Molecular Orbital Calculations

1981 ◽  
Vol 36 (11) ◽  
pp. 1246-1252 ◽  
Author(s):  
Michael H. Palmer ◽  
Isobel Simpson ◽  
J. Ross Wheeler
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
Relative Stability ◽  
Photoelectron Spectra ◽  
Equilibrium Geometry ◽  
Molecular Orbital Calculations ◽  
Methyl Derivatives

The photoelectron spectra of the tautomeric 1,2,3,- and 1,2,4-triazole and 1,2,3,4-tetrazole systems have been compared with the corresponding N-methyl derivatives. The dominant tautomers in the gas phase have been identified as 2 H-1,2,3-triazole, 1 H-1,2,4-triazole and 2H-tetrazole.Full optimisation of the equilibrium geometry by ab initio molecular orbital methods leads to the same conclusions, for relative stability of the tautomers in each of the triazoles, but the calculations wrongly predict the tetrazole tautomerism.

An ab initio study on some low-lying singlet and triplet states of SbO2+ and quartet states of SbO2

2006 ◽  
Vol 429 (4-6) ◽  
pp. 365-370 ◽  
Author(s):  
Edmond P.F. Lee ◽  
John M. Dyke ◽  
Foo-tim Chau ◽  
Wan-ki Chow ◽  
Daniel K.W. Mok
Keyword(s):  
Ab Initio ◽  
Triplet States ◽  
Ab Initio Study ◽  
Singlet And Triplet States

Prediction of Charge Transport Properties of Molecular Materials by Ab Initio Molecular Orbital Calculations

2000 ◽  
Vol 660 ◽  
Author(s):  
Wataru Sotoyama ◽  
Tomoaki Hayano ◽  
Hiroyuki Sato ◽  
Azuma Matsuura ◽  
Toshiaki Narusawa
Keyword(s):  
Charge Transport ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Electron Mobility ◽  
Molecular Orbital Calculations ◽  
Molecular Materials ◽  
Structural Reorganization ◽  
Charge Hopping ◽  
Reorganization Energies ◽  
A Charge

ABSTRACTWe developed a method to predict the charge transport (CT) type (hole or electron) in molecular materials that uses molecular orbital calculations. The hole-and-electron-mobility ratios of molecular materials were calculated based on molecular structural reorganization energies in a charge hopping process. The CT types predicted from the calculated mobility ratios agreed with those experimentally obtained in seven of the eight model molecules.

scholarly journals Effect of BrU on the transition between wobble Gua-Thy and tautomeric Gua-Thy base-pairs: ab initio molecular orbital calculations

2013 ◽  
Vol 433 ◽  
pp. 012035
Author(s):  
Kazuya Nomura ◽  
Ryota Hoshino ◽  
Yasuhiro Hoshiba ◽  
Victor I Danilov ◽  
Noriyuki Kurita
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Base Pairs
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