Valence Force Constants and Normal Vibrations of Methanol

1970 ◽  
Vol 25 (11) ◽  
pp. 1729-1731 ◽  
Author(s):  
A. Timidei ◽  
G. Zerbi
Keyword(s):  
Force Field ◽  
Molecular Spectroscopy ◽  
Harmonic Approximation ◽  
Force Constants ◽  
Least Square ◽  
Vibrational Modes ◽  
Normal Vibrations ◽  
Valence Force ◽  
Valence Force Field

Abstract The possibility of reproducing the normal vibrations of methanol, CH3OH, and its deutero-derivatives CH3OD, CD3OH, CD3OD using a valence force field has been critically analyzed. A 13 parameter valence force field has been determined by least square calculations. The meaning of the obtained numbers and their validity in molecular spectroscopy are discussed and compared with the information already available in the literature. It is concluded that the vibrational modes of this molecule are fairly well known within the harmonic approximation.

Molecular Force Fields of Tungsten and Uranium Hexachlorides

1972 ◽  
Vol 27 (4) ◽  
pp. 700-701 ◽  
Author(s):  
M.N. Avasthi ◽  
M.L. Mehta
Keyword(s):  
Force Field ◽  
Force Fields ◽  
Field Studies ◽  
Force Constants ◽  
Least Square ◽  
Valence Force ◽  
Valence Force Field ◽  
Weighted Least Square ◽  
Molecular Force ◽  
Molecular Force Field

Abstract Molecular force field studies of tungsten and uranium hexa-chloride have been carried out using the Urey-Bradley force field (UBFF) and the orbital valence force field (OVFF). Weighted least square adjustment has been used to fit the observed frequencies. Comments are also made on the suit-ability of the force fields used. The trends in stretching force constants have been discussed.

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).

Notizen:Schwingungseigenschaften des TeO42- -Ions/ Vibrational Properties of the TeO42--Ion

1978 ◽  
Vol 33 (10) ◽  
pp. 1226-1227
Author(s):  
Enrique J. Baran
Keyword(s):  
Force Field ◽  
Related Species ◽  
Force Constants ◽  
Vibrational Properties ◽  
Bond Orders ◽  
Mean Amplitudes Of Vibration ◽  
Valence Force ◽  
Valence Force Field ◽  
Complete Assignment

Abstract A complete assignment of the fundamental vibrations of the tetrahedral TeO42- ion is proposed and its principal force constants have been calculated using the modified valence force field. Mean amplitudes of vibration and bond orders are also estimated. The results are briefly discussed and some comparisons with related species are made.

On the application of OVFF to MX6 type ions

1972 ◽  
Vol 27 (5) ◽  
pp. 867-869 ◽  
Author(s):  
J. N. Rai ◽  
S. N. Tiwary ◽  
S. N. Rai
Keyword(s):  
Force Field ◽  
Point Group ◽  
Force Constants ◽  
Valence Force ◽  
Valence Force Field

AbstractForce constants for nine ions belonging to Oh point group have been evaluated by using Orbital Valence Force Field. The constants have been compared with their values obtained by using Urey-Bradley Force Field. The validity of the two methods has been discussed

Gitterschwingungsspektren

1976 ◽  
Vol 31 (7) ◽  
pp. 847-852 ◽  
Author(s):  
H. D. Lutz ◽  
P. Willich ◽  
H. Haeuseler
Keyword(s):  
Force Field ◽  
Long Range ◽  
Force Constants ◽  
The Other ◽  
Valence Force ◽  
Normal Coordinates ◽  
Valence Force Field ◽  
Symmetry Coordinates ◽  
Ir Frequencies ◽  
Good Agreement

Abstract Force constants and normal coordinates of MnS2 , FeS2 , RuS2, RuSe2, RuTe2, OsS2 and PtP2 are calculated based on the five ir active vibrations of the pyrite lattice. By setting up a valence force field consisting of short and long range M -X, X2 -X2 and M -M stretching constants it has proved possible to obtain good agreement between experimental and calculated frequencies with expection of FeS2 and RuS2 . The force constants corresponding to the shortest metal chalcogen distances (MnS2: 0.30, RuSe2: 0.88, RuTe2: 0.62, OsS2: 1.32, PtP2: 1.22 mdyn/Å) are mainly responsible for the ir frequencies. For RuSe2 and RuTe2, the forces between adjacent X2 groups are not negligible. Whereas the force constants of OsS2 and PtP2 are of comparable strength, the forces in MnS2 are significantly weaker than those in the other compounds. The normal coordinates of MnS2, OsS2 and PtP2 , and RuSe2 and RuTe2 show significant differences according to both the contribution of the 6 symmetry coordinates to the 5 ir active vibrations and the assignment of the spectra.

Darstellung und Schwingungsspektren von cis- und trans-[OsXY(acac)2], X ≠ Y = Cl, Br, I sowie Normalkoordinatenanalyse von trans-[OsClBr(acac)2]/Synthesis and Vibrational Spectra of cis- and trans-[OsXY(acac)2], X ≠ Y = Cl, Br, I, and Normal Coordinate Analysis of trans-[OsClBr(acac)2]

1998 ◽  
Vol 53 (2) ◽  
pp. 227-231
Author(s):  
K. Dallmann ◽  
W. Preetz
Keyword(s):  
Normal Coordinate Analysis ◽  
Force Constants ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Stretching Vibrations ◽  
Cis And Trans ◽  
Ir And Raman ◽  
Good Agreement

Abstract In the reaction of K2[OsX3 Y3] with boiling water/acetylacetone (1:1) the six mixed com­plexes cis-and trans-[OsX2 (acac)2] (X ≠ Y = Cl, Br, I) are formed, which have been purified by column chromatography with toluene on silica gel. The IR and Raman spectra (10K) show the intraligand vibrations of the acac groups with nearly constant frequencies and the stretching vibrations of OsO in the range 460-696, of OsCl at 315-345, of OsBr at 210-225, and of Osl at 160-175 cm-1 . A normal coordinate analysis based on a modified valence force field was performed for trans-[OsClBr(acac)2] and the vibrational modes have been assigned. With a set of 32 force constants, taking into account the intraligand vibrations, a good agreement between observed and calculated frequencies has been achieved. The valence force constants are fd (OsCl•) = 1.75, fd(OsBr′) = 1.63 and fd (OsO) = 3.27 mdyn/Å.

New Measurements of the Infrared Spectrum of H2S2 and D2S2 and Evaluation of the Molecular Force Field

1968 ◽  
Vol 23 (6) ◽  
pp. 832-839 ◽  
Author(s):  
Brenda P. Winnewisser ◽  
Manfred Winnewisser
Keyword(s):  
Infrared Spectrum ◽  
Force Field ◽  
Force Constants ◽  
Valence Force ◽  
Valence Force Field ◽  
Fundamental Frequencies ◽  
New Information ◽  
Molecular Force ◽  
Combination Bands ◽  
First Time

The infrared spectrum of H2S2 has been reviewed in the range 4000 to 250 cm-1 and the spectrum of D2S2 has been measured for the first time. No change in the basic assignment of the fundamental bands of H2S2 has been made, although the stretching fundamentals and the combination bands can be more precisely assigned on the basis of the new information.With the six fundamental frequencies of H2S2 and the two asymmetric fundamental frequencies of D2S2 , calculations were made to determine as fully as possible the general valence force field. It was found that only the diagonal force constants could be determined on the basis of the available data:FSH = 4.08 - 4.09 md/Å, Fa = 0.83 - 0.85 md A/rad2,FSS = 2.52 -2.62 md/Å, Ft = 0.0926 md Å/rad2.

Orbital Valence Force Field Constants of Tetrachlorides, Tetrabromides and Tetraiodides of Titanium, Zirconium and Hafnium

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1211-1212
Author(s):  
A. N. Pandey ◽  
D. Sharma ◽  
H. Mital
Keyword(s):  
Force Field ◽  
Relative Strength ◽  
Force Constants ◽  
Jones Potential ◽  
Valence Force ◽  
Valence Force Field ◽  
Lennard Jones ◽  
Titanium Zirconium ◽  
Raman Spectral Data ◽  
Raman Spectral

Abstract The orbital valence force field has been employed to calculate the force constants for tetra-chlorides, tetrabromides, and tetraiodides of titanium, zirconium, and hafnium making use of recent vapor-phase Raman spectral data. The results are compared with the Urey-Bradley force constants, and it has been found that these are well comparable. The applicability of the Lennard-Jones potential has been examined to understand the nature of non-bonded interactions. The force constants have also been utilized to study the relative strength of the chemical bonds in tetrahalides and hexahalide anions

Schwingungsspektren und Kraftkonstanten der Hexahalogeno-Komplexe des Technetium(IV) und Rhenium(IV)

1969 ◽  
Vol 24 (3) ◽  
pp. 403-407 ◽  
Author(s):  
Klaus Schwochau ◽  
Wolfgang Krasser
Keyword(s):  
Force Field ◽  
Infrared Spectra ◽  
Force Constants ◽  
Octahedral Structure ◽  
Fundamental Vibration ◽  
Rhenium Complexes ◽  
Valence Force ◽  
Valence Force Field ◽  
Bond Stretching

The Raman and infrared spectra of the potassium and caesium salts of [TcX6]-- and [ReX6]-- (X = F, Cl, Br, I) have been measured in the range from 1000 to 45 cm-1. The force constants are determined in the valence force field and in the standard Urey-Bradley field on the basis of the Oh-symmetry. The fundamental vibration ν6 is calculated from the force constants. Apart from the fluoro-compounds the bond-stretching force constants of the technetium complexes are shown to be smaller than those of the analogous rhenium complexes. Except for the iodo-compounds a distortion of the octahedral structure progressive in degree towards X = F can be concluded from the splitting of degeneracies.

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