The effect of p, d, and f Gaussian polarization functions on the computed one-electron properties of AHn oxygen and sulfur hydrides

1978 ◽  
Vol 56 (4) ◽  
pp. 543-551 ◽  
Author(s):  
Raymond Poirier ◽  
Roy Kari
Keyword(s):  
Basis Sets ◽  
Gaussian Type ◽  
Field Gradients ◽  
Isoelectronic Series ◽  
Monotonic Convergence ◽  
Polarization Functions ◽  
Scf Calculations ◽  
Made In ◽  
Lcao Mo

A series of LCAO-MO-SCF calculations, using various basis sets of Gaussian-type functions, has been made in order to study the effects of p, d, and f polarization functions on calculated one-electron properties for a 10-electron isoelectronic series of oxygen hydrides and for an 18-electron series of sulfur hydrides. Conclusions from these results suggest that several one-electron properties have a predictable, although not monotonic convergence pattern. Except for calculated field gradients, f GPF's have only a small effect on the calculated values.

Geometries of the ground and first excited triplet states of thioformaldehyde

1981 ◽  
Vol 59 (22) ◽  
pp. 3200-3203 ◽  
Author(s):  
John D. Goddard
Keyword(s):  
Ground State ◽  
Reasonable Agreement ◽  
Basis Sets ◽  
Triplet States ◽  
Gaussian Basis Sets ◽  
Excited Triplet ◽  
Polarization Functions ◽  
Scf Calculations ◽  
Split Valence ◽  
Excited Triplet States

The geometries of the S0 and T1 states of thioformaldehyde are determined by ab initio SCF calculations with Gaussian basis sets ranging from minimal to double ζ plus both diffuse and polarization functions. The ground state geometries are all in reasonable agreement with experiment but for the n → π* triplet state split valence or double ζ basis sets yield unreasonably long CS bond distances.

Theoretical predictions of the molecular structure of sulphur tetrafluoride

1975 ◽  
Vol 28 (9) ◽  
pp. 2069 ◽  
Author(s):  
L Radom ◽  
III HF Schaefer
Keyword(s):  
Basis Set ◽  
Basis Sets ◽  
Structure Theory ◽  
Equilibrium Geometry ◽  
Double Zeta ◽  
Theoretical Predictions ◽  
Self Consistent Field ◽  
Polarization Functions ◽  
Hypervalent Molecules ◽  
Scf Calculations

The equilibrium geometry of the SF4 molecule has been investigated by means of ab initio electronic structure theory. Self-consistent-field (SCF) calculations employing a minimum basis set (MBS) incorrectly predict SF4 to have a square- pyramidal (C4V) structure. The correct qualitative prediction of a C2V geometry is obtained with a basis of nearly double zeta quality. Comparable calculations on H2S and SF2 suggest that it may only be for hypervalent molecules containing sulphur that minimum basis sets are inappropriate. However, polarization functions seem to be necessary for an accurate prediction of S-F bond distances.

Ab Initio Calculations of the Molecular Structures and the Electronic Properties of Phospha-AlkynesR-C≡P(R=H,CH3,NH2,OH, F and Cl)

1984 ◽  
Vol 39 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Minh Tho Nguyen
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electronic Properties ◽  
Molecular Structures ◽  
Basis Sets ◽  
Effect Of Substituents ◽  
Force Method ◽  
Double Zeta ◽  
Polarization Functions ◽  
Scf Calculations

Results of ab initio SCF calculations on phospha-alkynes R-C≡P with R=H. CH3, NH2, OH. F and Cl are reported. The geometries were optimized by the force method with analytical gradient employing double zeta (DZ) basis sets. Various molecular and one-electron properties are calculated with double zeta plus polarization functions (DZ + P) and compared with experimental ones. The effect of substituents is analysed in terms of computed properties.

scholarly journals DFT calculation and assignment of vibrational spectra of aryl and alkyl chlorophosphates

2014 ◽  
Vol 12 (2) ◽  
pp. 153-163
Author(s):  
Viktor Anishchenko ◽  
Vladimir Rybachenko ◽  
Konstantin Chotiy ◽  
Andrey Redko
Keyword(s):  
Vibrational Spectra ◽  
Basis Sets ◽  
Heavy Atoms ◽  
Wide Range ◽  
Complete Assignment ◽  
Key Factor ◽  
Polarization Functions ◽  
Experimental Values ◽  
Semi Empirical ◽  
Good Agreement

AbstractDFT calculations of vibrational spectra of chlorophosphates using wide range of basis sets and hybrid functionals were performed. Good agreement between calculated and experimental vibrational spectra was reached by the combination of non-empirical functional PBE0 with both middle and large basis sets. The frequencies of the stretching vibrations of the phosphate group calculated using semi-empirical functional B3LYP for all basis sets deviate significantly from the experimental values. The number of polarization functions on heavy atoms was shown to be a key factor for the calculation of vibrational frequencies of organophosphates. The importance of consideration of all the stable rotamers for a complete assignment of fundamental modes was shown.

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