Cation-ligand interactions: Reproduction of extended basis set Ab initio SCF computations by the SIBFA 2 additive procedure

1985 ◽  
Vol 28 (6) ◽  
pp. 757-771 ◽  
Author(s):  
N. Gresh ◽  
A. Pullman ◽  
P. Claverie
Keyword(s):  
Ab Initio ◽  
Basis Set ◽  
Ligand Interactions ◽  
Extended Basis

Ab initio fully relativistic molecular calculations: bonding in gold hydride

1986 ◽  
Vol 407 (1833) ◽  
pp. 377-404 ◽  
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Gold Atom ◽  
Basis Set ◽  
Minor Role ◽  
Atomic Unit ◽  
Fundamental Vibration ◽  
Free Gold ◽  
Self Consistent Field ◽  
Extended Basis

The electronic structure of gold hydride is investigated by ab initio fully relativistic extended basis set self-consistent field and configuration interaction calculations based on the Dirac equation. The gold 6p orbitals play only a very minor role in the bonding. The ten electrons occupying the 5d orbitals in the free gold atom are significantly affected by the formation of the molecule whose electronic structure exhibits substantial 5d‒6s hybridization. The extended-basis calculations show that relativity shortens the bond length by 0.45 a. u. (1 a. u. (atomic unit) of length = 1 bohr ≈ 0.529177 × 10 ‒10 m), substantially increases the fundamental vibration frequency and doubles the binding energy predicted by using a single determinant wavefunction. The bonding cannot be fully understood by using non-relativistic theory.

The Rotational Barrier About the Disulphide Bridge in Dimethyl Disulphide: An Ab Initio Study

1984 ◽  
Vol 39 (5) ◽  
pp. 495-498
Author(s):  
V. Renugopalakrishnan ◽  
R. Walter
Keyword(s):  
Ab Initio ◽  
Rotational Barrier ◽  
Basis Set ◽  
Basis Sets ◽  
Disulphide Bridge ◽  
Minimal Basis ◽  
Gaussian Basis Sets ◽  
Type Function ◽  
Dimethyl Disulphide ◽  
Extended Basis

An ab initio molecular orbital technique was used to investigate the rotational barrier about the disulphide bridge in dimethyl disulphide. Various minimal and extended basis sets were used in the calculations. The chosen minimal basis set was the STO-3G set, and the extended basis sets were the STO 4-31G set, the Dunning and Hay set consisting of contracted Gaussian basis sets: [2s], [3s, 2p] and [6s, 4p] for H, C, and S atoms, and the Dunning and Hay basis set augmented with a d-type function on S atoms. The total energy was calculated as a function of the torsion angle about the disulphide bond. The barrier to rotation about this bond was found to be two-fold in nature, in accordance with previous findings. The heights of the barriers were observed to depend upon the basis set and input geometry. For our particular choice of basis sets and input geometry, the calculated value of the eis and trans barriers ranged from 12.68 to 16.49 kcal/mol and from 6.23 to 8 kcal/mol, respectively. Inclusion of a d-type function in the basis sets was found to result in better agreement between the calculated and experimental values, thereby emphasizing the need for considering 3d orbitals of sulphur in MO calculations

scholarly journals An extended basis set ab initio study of Li+(H2O)n, n=1–6

1994 ◽  
Vol 100 (7) ◽  
pp. 4981-4997 ◽  
Author(s):  
David Feller ◽  
Eric D. Glendening ◽  
Rick A. Kendall ◽  
Kirk A. Peterson
Keyword(s):  
Ab Initio ◽  
Basis Set ◽  
Ab Initio Study ◽  
Extended Basis

Conformational Preference in CH3, CH2F and CF3 Compounds of 1st and 2nd Row Elements

1986 ◽  
Vol 39 (5) ◽  
pp. 747 ◽  
Author(s):  
E Magnusson
Keyword(s):  
Ab Initio ◽  
Structural Relaxation ◽  
Basis Set ◽  
Ab Initio Study ◽  
Conformational Preference ◽  
Extended Basis

Energy changes and differences in geometries between the staggered and eclipsed conformations of methyl-, fluoromethyl - and trifluoromethyl - substituted compounds have been determined in a systematic ab initio study of compounds of first and second row elements. Geometry-optimized results at extended basis set level obtained on SiH3X, SiH2X-, PH3X+, PH2X, PHX-, SH2X+ and SHX species (X = CH3, CH2F, CF3) are compared with data on the corresponding first row compounds. The structural relaxation accompanying rotation in methyl compounds of second row elements is smaller than it is in compounds of the first row but for X = CF3 the geometrical changes are comparable. However, the relaxation contribution to energy is much smaller in the heavier compounds.

An extended basis set ab initio study of alkali metal cation–water clusters

1995 ◽  
Vol 103 (9) ◽  
pp. 3526-3542 ◽  
Author(s):  
David Feller ◽  
Eric D. Glendening ◽  
David E. Woon ◽  
Martin W. Feyereisen
Keyword(s):  
Alkali Metal ◽  
Ab Initio ◽  
Metal Cation ◽  
Water Clusters ◽  
Alkali Metal Cation ◽  
Basis Set ◽  
Ab Initio Study ◽  
Extended Basis
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