Bestimmung der Kraftkonstanten der Hexafluoro-Komplexe des Technetium(IV) und Rhenium(IV) auf der Basis der D4h-Symmetrie

1970 ◽  
Vol 25 (2) ◽  
pp. 206-210 ◽  
Author(s):  
Wolfgang Krasser ◽  
Klaus Schwochau
Keyword(s):  
Force Field ◽  
Infrared Spectra ◽  
Force Constants ◽  
Irreducible Representations ◽  
Octahedral Complex ◽  
Site Symmetry ◽  
Complex Ions ◽  
Linear Combinations ◽  
Valence Force Field ◽  
Stretching Vibrations

Abstract The infrared spectra of potassium and cesium hexafluorotechnetate (IV) and -rhenate(IV) show a D4h-distortion of the octahedral complex ions. The splitting of degeneracies is not due to site symmetry. The linear combinations of the force constants of the irreducible representations A2u and Eu are determined in the valence force field on the basis of D4h-symmetry. As expected the force constants of stretching vibrations of [TcF6]-- are then smaller than those of [ReF6]--.

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).

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.

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.

Force field of acetic acid: use of CNDO/force calculations

1983 ◽  
Vol 61 (2) ◽  
pp. 263-266 ◽  
Author(s):  
A. Annamalai ◽  
Surjit Singh
Keyword(s):  
Acetic Acid ◽  
Potential Energy ◽  
Force Field ◽  
Force Fields ◽  
Force Constants ◽  
Energy Distributions ◽  
Valence Force Field ◽  
Bending Force ◽  
Set Up ◽  
Initial Force

The redundancy-free internal valence force field of monomeric acetic acid is evaluated using CNDO/force calculations and least-squares refinement. The initial force field is set up by taking the interaction and bending force constants from CNDO force field and transferring the stretching force constants from the force fields of chemically related molecules. Vibrational frequencies of monomeric CH3COOH, CH3COOD, CD3COOH, and CD3COOD are used to refine the force constants. The experimental force field thus obtained is found to be reasonable when compared to the force fields of related molecules as well as on the basis of the frequency fits and potential energy distributions.

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.

Vibrational analysis and force field for some secondary iodides

1977 ◽  
Vol 55 (2) ◽  
pp. 310-317 ◽  
Author(s):  
G. Crowder ◽  
Zahra Najafi
Keyword(s):  
Force Field ◽  
Infrared Spectra ◽  
Vibrational Analysis ◽  
Zero Order ◽  
Average Error ◽  
Average Difference ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Wave Numbers

Normal coordinate calculations were made for 2-iodopropane and the three conformers of 2-iodobutane. A forty-seven parameter modified valence force field was used that fit eighty-four frequencies of those four molecules in the 250–1500 cm−1 region with an average error of 4.8 cm−1, or 0.6%. Infrared spectra were obtained for 2-iodopentane and 3-iodopentane, and zero-order normal coordinate calculations were made for three conformers of 2-iodopentane and for five conformers of 3-iodopentane. The SHH, SHH′, and SCH conformers of 2-iodopentane are present, along with one or two unidentified ones, and 3-iodopentane exists as a mixture of the SHH, SHH′, SCH, and SCH′ conformers. The force constants that were determined for the four conformers of 2-iodopropane and 2-iodobutane were transferred to the two secondary iodo-pentanes with good success. The average difference between observed and calculated wave-numbers for 164 frequencies of seven conformations of these two compounds was 5.8 cm−1.

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