Computation of large systems with an economic basis set: Ab initio calculations of silicon oxide clusters

2001 ◽  
Vol 114 (13) ◽  
pp. 5531-5536 ◽  
Author(s):  
R. Q. Zhang ◽  
T. S. Chu ◽  
S. T. Lee
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Silicon Oxide ◽  
Basis Set ◽  
Economic Basis ◽  
Large Systems

Vicinal proton—proton coupling constants. Basis set dependence in SCF ab initio calculations

1993 ◽  
Vol 206 (1-4) ◽  
pp. 253-259 ◽  
Author(s):  
Jesús San-Fabián ◽  
Joaquín Guilleme ◽  
Ernesto Díez ◽  
Paolo Lazzeretti ◽  
Massimo Malagoli ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Coupling Constants ◽  
Basis Set ◽  
Proton Proton ◽  
Proton Coupling ◽  
Vicinal Proton

scholarly journals Geometric and Energetic Data from Ab Initio Calculations of Haloethene, Haloimine, Halomethylphosphine, Haloiminophosphine, Halodiazene, Halodiphosphene and Halocyclopropane

2019 ◽  
Author(s):  
Kridtin Chinsukserm ◽  
Wanutcha Lorpaiboon ◽  
Peerayar Teeraniramitr ◽  
Taweetham Limpanuparb
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Theoretical Data ◽  
Geometric Optimization ◽  
Basis Set ◽  
Halogenated Compounds ◽  
Wolfram Mathematica

<p>This article presents theoretical data on geometric and energetic features of halogenated compounds of cyclopropane (∆) and ethene (C=C), imine (C=N), methylphosphine (C=P), iminophosphine (N=P), diazene (N=N) and diphosphene (P=P). The data were obtained from <i>ab initio</i> geometric optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. Input structures were generated by shell scripts and run by Q-Chem quantum chemical package. The output files were processed to extract geometric and energetic information by Wolfram Mathematica.</p>

Conformational Structure of Chloromethyldichlorophosphines

2002 ◽  
Vol 57 (6-7) ◽  
pp. 333-336
Author(s):  
Evgenii A. Romanenko ◽  
Alexander M. Nesterenko
Keyword(s):  
Experimental Data ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electron Correlation ◽  
Basis Set ◽  
Conformational Structure ◽  
Gauche Conformation ◽  
Nuclear Quadrupole ◽  
Set Up ◽  
Good Agreement

IThe 35Cl nuclear quadrupole resonances (77 K) and ab initio calculations of trichloromethyldichlorophosphine () show that it exists in the chess conformation form. The barrier to internal rotation about the P-C bond in I at the RHF/6-31++ G(d,p) level equals to 38.1 kJ mol-1. In chloromethyldichlorophosphine (II) the extension of the basis set up to the RHF/6-311++G(df, pd) level does not improve the description of the most preferable gauche-conformation; only if electron correlation (at the MP2 level) is taken into account the results are in a good agreement with experimental data.

On the tautomerism of 1-phenyl-3-substituted-pyrazol-5-ones and their photoinduced products — experimental and theoretical UV spectral analysis

2008 ◽  
Vol 62 (3) ◽  
Author(s):  
Atanas Chapkanov ◽  
Bojidarka Koleva ◽  
Michail Arnaudov ◽  
Ivan Petkov
Keyword(s):  
Spectral Analysis ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Uv Spectra ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Tautomeric Forms

AbstractA detailed experimental and theoretical UV-spectral analysis of the tautomeric forms of 3-methyl-1-phenyl pyrazol-5-one and 1,3-diphenyl pyrazol-5-one as well as of the UV-irradiated photoinduced products of the latter compound were carried out. The experimental UV-spectra were compared with the theoretical ones obtained by CIS/6-31G**. Selected geometrical parameters of the different tautomers were estimated by ab initio calculations using the RHF/6-31G** level of theory and basis set, which have also been discussed with a view to the corresponding UV-results.

Ab Initio Calculations of the Molecular Structures and the Electronic Properties of Sulfur-containing Compounds: III. Thioacrolein (CH2=CH–CH=S) and Thioglyoxal (S = CH–CH=S)

1982 ◽  
Vol 37 (2) ◽  
pp. 125-128
Author(s):  
Tae-Kyu Ha ◽  
M. T. Nguyen ◽  
L. Vanquickenborne
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electronic Properties ◽  
Gradient Method ◽  
Molecular Structures ◽  
Basis Set ◽  
Double Zeta ◽  
Scf Calculations ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds

Abstract Results of ab initio SCF calculations on thioacrolein (CH2=CH-CH=S) and thioglyoxal (S=CH-CH=S) are reported. The geometries are optimized by the analytical gradient method using the double zeta (DZ) basis set. The trans conformers of these molecules are calculated to be more stable than the cis conformer by 2.06 and 4.31 kcal/mol, respectively.

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