Photoelectron Spectra, Ab Initio SCF MO, and Natural Bond Orbital Studies on Stellenes. Long-Range π/σ Interactions

1996 ◽  
Vol 118 (20) ◽  
pp. 4889-4895 ◽  
Author(s):  
Rolf Gleiter ◽  
Holger Lange ◽  
Oliver Borzyk
Keyword(s):  
Ab Initio ◽  
Long Range ◽  
Natural Bond Orbital ◽  
Photoelectron Spectra

Long-Range σ−π Interactions in Tetrahydro-4H-thiopyran End-Capped Oligo(cyclohexylidenes). Photo-Electron Spectroscopy, ab Initio SCF MO Calculations, and Natural Bond Orbital Analyses

2000 ◽  
Vol 65 (15) ◽  
pp. 4584-4592 ◽  
Author(s):  
Albert W. Marsman ◽  
Remco W. A. Havenith ◽  
Sabine Bethke ◽  
Leonardus W. Jenneskens ◽  
Rolf Gleiter ◽  
...  
Keyword(s):  
Ab Initio ◽  
Long Range ◽  
Electron Spectroscopy ◽  
Natural Bond Orbital ◽  
Mo Calculations ◽  
Π Interactions

scholarly journals A simplified charge projection scheme for long-range electrostatics in ab initio QM/MM calculations

2021 ◽  
Vol 154 (2) ◽  
pp. 024115
Author(s):  
Xiaoliang Pan ◽  
Kwangho Nam ◽  
Evgeny Epifanovsky ◽  
Andrew C. Simmonett ◽  
Edina Rosta ◽  
...  
Keyword(s):  
Ab Initio ◽  
Long Range ◽  
Projection Scheme

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.

VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES

2002 ◽  
Vol 09 (01) ◽  
pp. 153-158 ◽  
Author(s):  
WEIDONG ZHOU ◽  
D. P. SECCOMBE ◽  
R. Y. L. CHIM ◽  
R. P. TUCKETT
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Ground State ◽  
Lower Energy ◽  
Lone Pair ◽  
Electronic States ◽  
Photoelectron Spectra ◽  
Highest Occupied Molecular Orbital ◽  
Impulsive Model ◽  
Lone Pair Electrons

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.

Photoelectron spectra of and ab initio calculations on chlorobenzenes. 3. Hexachlorobenzene

1981 ◽  
Vol 85 (11) ◽  
pp. 1495-1497 ◽  
Author(s):  
Branko Ruscic ◽  
Leo Klasinc ◽  
Andreas Wolf ◽  
Jan V. Knop
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Photoelectron Spectra

A study of the vacuum pyrolysis of 1,2,3-benzotriazines. The Hel ultraviolet photoelectron spectra of benzazete and o-benzyne

1995 ◽  
Vol 73 (1) ◽  
pp. 146-149 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
Chandra Deo Roy ◽  
Jiangong Ma
Keyword(s):  
Heat Source ◽  
Ab Initio ◽  
Photoelectron Spectra ◽  
Equilibrium Geometry ◽  
Ionization Energies ◽  
Vacuum Pyrolysis ◽  
Ab Initio Hf

A CW CO2 laser is used as a directed heat source to carry out the vacuum pyrolysis of 1,2,3-benzo-triazine (1a) and 4-methyl-1,2,3-benzotriazine (1b). We report the first HeI photoelectron (pe) spectrum of benzazete (2a), which correlates with ionization energies calculated with HAM/3 using an equilibrium geometry obtained at the ab initio HF/6-31G** level of the theory. The pe spectrum of o-benzyne (3) obtained in this study correlates with the spectrum published by Zhang and Chen, but not with the spectra reported in two earlier publications. Keywords: 1,2,3-benzotriazines, vacuum pyrolysis, HeI ultraviolet photoelectron spectra, benzazete, benzyne.

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