Harmonic force field: An approximate relationship between the exact nonrelativistic and the Hartree–Fock limit values of the force constants

1991 ◽  
Vol 94 (2) ◽  
pp. 1247-1252 ◽  
Author(s):  
Vladimir I. Pupyshev ◽  
Yurii N. Panchenko ◽  
Charles W. Bock ◽  
Gábor Pongor
Keyword(s):  
Force Field ◽  
Force Constants ◽  
Harmonic Force ◽  
Limit Values ◽  
Hartree Fock ◽  
Approximate Relationship

Calculation of harmonic force constants from Hartree-Fock-Roothaan wavefunctions

1971 ◽  
Vol 20 (6) ◽  
pp. 1135-1146 ◽  
Author(s):  
Peter Swanstrøm ◽  
Knud Thomsen ◽  
Peter B. Yde
Keyword(s):  
Force Constants ◽  
Harmonic Force ◽  
Hartree Fock

An ab initio Calculation of the Force Constants, Vibrational Frequencies, and Equilibrium Geometry of HCP

1975 ◽  
Vol 30 (8) ◽  
pp. 1015-1017 ◽  
Author(s):  
P. Botschwina ◽  
K. Pecul ◽  
H. Preuss
Keyword(s):  
Ab Initio ◽  
Ab Initio Calculation ◽  
Relaxation Method ◽  
Force Constants ◽  
Equilibrium Geometry ◽  
Harmonic Force ◽  
Hartree Fock ◽  
Force Method ◽  
Force Relaxation ◽  
Good Agreement

Abstract All the harmonic, the diagonal cubic and quartic stretching and the semidiagonal cubic force constants of HCP have been calculated from Hartree-Fock wavefunctions by the force method of Pulay. The force constants are in good agreement with the experimental ones, except for FRR, Faa, FRr, FRaa, and Fraa the latter two being rather uncertain from experiment. From the harmonic force constants, harmonic frequencies have been calculated by the method of Wilson and Eliashevich. The equilibrium geometry of HCP has been calculated by the force relaxation method of Pulay.

Vibrational spectra of stannane: Harmonic force field, Raman and IR intensities from ab initio correlated wavefunctions

1989 ◽  
Vol 130 (1-3) ◽  
pp. 451-456 ◽  
Author(s):  
Javier Fernandez Sanz ◽  
Antonio Marquez ◽  
Claude Pouchan
Keyword(s):  
Force Field ◽  
Ab Initio ◽  
Vibrational Spectra ◽  
Harmonic Force ◽  
Ir Intensities

Symmetry Coordinates, Harmonic Force Field, and Mean Amplitudes for Light and Heavy Dibenzene Chromium

1971 ◽  
Vol 54 (4) ◽  
pp. 1517-1522 ◽  
Author(s):  
S. J. Cyvin ◽  
J. Brunvoll ◽  
Lothar Schäfer
Keyword(s):  
Force Field ◽  
Harmonic Force ◽  
Symmetry Coordinates

Schwingungsspektren und Kraftkonstanten der Hexacyano-Komplexe des Mangan(I), Technetium(I) und Rhenium(I) / Vibrational Spectra and Force Constants of the Hexacyano Complexes of Mangan(l), Technicium(I) and Rhenium(l)

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1193-1196 ◽  
Author(s):  
W. Krasser ◽  
K. Schwochau
Keyword(s):  
Force Field ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Point Group ◽  
Force Constants ◽  
Irreducible Representations ◽  
Infrared And Raman Spectra ◽  
Valence Force ◽  
Valence Force Field ◽  
Complex Salts

The infrared and Raman spectra of the complex salts K5[Mn(CN)6], K5[Tc(CN)6] and K5[Re(CN)s] have been recorded in the range from 4000 to 40 cm-1. All expected fundamental vibrations have been observed and could be assigned to the irreducible representations of the sym­metry point group Oh . The calculation of the force constants is based on the concept of the generalized valence force field. The low CN-valence force constants indicate the relatively strong Π-bonding character of the metal carbon bond, which is especially pronounced for K5[Tc(CN)6).

The microwave spectrum of the ClS2 free radical

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1043-1050 ◽  
Author(s):  
Masaharu Fujitake ◽  
Eizi Hirota
Keyword(s):  
Free Radical ◽  
Force Field ◽  
Electronic Spectroscopy ◽  
Spin Rotation ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Harmonic Force ◽  
Isotopic Species ◽  
Spin Resonance ◽  
Centrifugal Distortion Constants

The rotational spectrum of the ClS2 free radical in the gaseous phase has been observed in the millimetre- and submillimetre-wave regions. The ClS2 radical was generated by a dc glow discharge in either S2Cl2 or SCl2. Both a- and b-type R-branch transitions, most of which were split into two fine structure components, were detected for both of the 35Cl and 37Cl isotopic species in the ground vibronic state. As expected from the small hyperfine interaction constants reported by an electron spin resonance (ESR) study, the hyperfine structure was resolved for none of the transitions observed in the present study. Analysis of the observed transition frequencies yielded rotational and centrifugal distortion constants and also spin–rotation interaction constants with their centrifugal corrections. The spin–rotation interaction constants obtained in the present study were consistent with g values of the ESR study. The rotational constants of the two isotopic species led to the structure parameters r(S—S) = 1.906 (7) Å, r(S—Cl) = 2.071 (5) Å, and θ(SSCl) = 110.3 (4)°. A harmonic force field was derived from the observed centrifugal distortion constants and inertial defects combined with the ν1 frequency reported in literature on electronic spectroscopy. This harmonic force field yielded the ν2 and ν3 frequencies (445 (21) and 213.0 (2) cm−1, respectively, for 35ClS2), which differed considerably from the values reported previously.

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