Adaptation of the Gelius intensity model in semiempirical HAM/3 molecular orbital calculations of valence photoelectron spectra excited by X-ray radiation

1985 ◽  
Vol 63 (7) ◽  
pp. 2007-2011 ◽  
Author(s):  
Delano P. Chong
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Cross Sections ◽  
Present Method ◽  
Photoelectron Spectra ◽  
Molecular Orbital Calculations ◽  
Ionization Energies ◽  
X Ray ◽  
Hartree Fock ◽  
Intensity Model

The Gelius intensity model has been adapted in the semiempirical HAM/3 method to calculate the valence ionization energies and intensities in XPS. Both semiempirical and àb initio Hartree–Fock–Slater atomic photoionization cross-sections can be used. Results presented for C2H2, C2H4, N2, H2O, CH3OH, and CH2F2 demonstrate that the present method can facilitate the interpretation of experimental XPS.

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.

The electronic structure of some heterocycles with bridgehead nitrogen: photoelectron spectra and ab initio molecular orbital calculations

1977 ◽  
Vol 42 ◽  
pp. 85-101 ◽  
Author(s):  
Michael H. Palmer ◽  
Derek Leaver ◽  
John D. Nisbet ◽  
Ross W. Millar ◽  
Russell Egdell
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Photoelectron Spectra ◽  
Molecular Orbital Calculations ◽  
Bridgehead Nitrogen

Nitrosyl cyanide and related aspects of the ONCN potential surface

1978 ◽  
Vol 31 (11) ◽  
pp. 2349 ◽  
Author(s):  
BG Gowenlock ◽  
L Radom
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Related Species ◽  
Potential Surface ◽  
Basis Sets ◽  
Molecular Orbital Calculations ◽  
Hartree Fock ◽  
Split Valence ◽  
Good Agreement

Ab initio molecular orbital calculations using the restricted Hartree-Fock approach have been carried out for nitrosyl cyanide and related species on the ONCN potential surface. Full geometry optimizations have been performed with the minimal STO-3G and split-valence 4-31G basis sets. Calculated (4-31G) geometries are in good agreement with available experimental data as are the energy changes in the reactions ONCN → NO + CN and NO + CN → N2 + CO. Possible mechanisms are discussed.

The Photoelectron Spectra of the N-Chloro and N-Bromo Derivatives of Dimethylamine

1979 ◽  
Vol 32 (4) ◽  
pp. 719 ◽  
Author(s):  
F Carnovale ◽  
T Gan ◽  
JB Peel
Keyword(s):  
Energy Range ◽  
Molecular Orbital ◽  
Ionization Energy ◽  
Lone Pair ◽  
Photoelectron Spectra ◽  
Molecular Orbital Calculations ◽  
Ionization Energies ◽  
Resonance Effects ◽  
Derivatives Of ◽  
Lone Pair Interactions

The He I and He II spectra obtained for chlorodimethylamine (CH3)2NCl, and bromodimethylamine (CH3)2NBr, complete the study of the N-chloro and N-bromo derivatives of the small amines. The valence photoelectron spectra are interpreted with the aid of SPINDO molecular orbital calculations. Trends in the observed ionization energies for both series of small halo amines are described in terms of variations in inductive and resonance effects, the latter particularly concerning the nN/nx lone-pair interactions observed in the low ionization energy range.

Valence ionization energies of Ni(CN) 2? 4 , CO(CN) 3? 6 and Fe(CN) 4? 6 , studied by X-ray emission spectroscopy and ab initio molecular-orbital methods

1988 ◽  
Vol 84 (2) ◽  
pp. 209 ◽  
Author(s):  
Stephen Smith ◽  
David A. Taylor ◽  
Ian H. Hillier ◽  
Mark A. Vincent ◽  
Martyn F. Guest ◽  
...  
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Emission Spectroscopy ◽  
Ionization Energies ◽  
X Ray

Solvation Structure of Solvated Cu(I) Ions in Non-Aqueous Solvents as Studied by EXAFS and ab initio Molecular Orbital Methods

1999 ◽  
Vol 54 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Y. Inada ◽  
Y. Tsutsui ◽  
H. Wasada ◽  
S. Funahashi
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Steric Effect ◽  
Molecular Orbital Calculations ◽  
Enthalpy Of Solvation ◽  
Octahedral Structure ◽  
X Ray ◽  
Solvation Structure ◽  
Solvent Molecules ◽  
X Ray Absorption

The structure parameters around the Cu(I) ion in pyridine (PY), 4-methylpyridine (4MPY), 2-methylpyridine (2MPY), 2,6-dimethylpyridine (26DMPY), and acetonitrile (AN) were determined by the extended X-ray absorption fine structure (EXAFS) method. The solvation structures of the Cu(I) ion in PY, 4MPY, and AN are 4-coordinate tetrahedral with Cu-N bond lengths of 205, 205, and 200 pm, respectively. In the case of 2MPY and 26DMPY, the Cu(I) ion has a 3-coordinate triangular structure with a Cu-N bond length of 201 pm. Such a decrease in the coordination number was interpreted in terms of the bulkiness of the solvent molecules. In order to clarify the most stable solvation structure of the Cu(I) ion, we carried out ab initio molecular orbital calculations for the solvation system of [Cu(NCH)n]+ (n = 1 - 6 ) where the steric effect is negligible. The Gibbs free energy of solvation was the smallest in the case of n = 4 and the 4-coordinate tetrahedral solvation of the Cu(I) ion was theoretically evaluated as most stable. The enthalpy of solvation monotonously decreases with increasing n, while the entropy of solvation proportionally increases. Although a larger gain of enthalpy is observed for the octahedral structure rather than the tetrahedral one, the entropic loss for the former overcomes the enthalpic gain.

Sign in / Sign up

Export Citation Format

Share Document