Schwingungsberechnungen des Hexathiometadiphosphatanions P2S62-

1988 ◽  
Vol 43 (5) ◽  
pp. 494-496 ◽  
Author(s):  
Lothar Ohse ◽  
Wolfgang Brockner

A normal coordinate analysis for the Hexathiometadiphosphate anion P2S62- was performed, based on a simple initial force field. The force field was refined by adjusting the symmetry force constants to approximate the observed frequencies. The final force field, potential energy distribution (PED) and mean amplitudes of vibration are also given. Based on the normal coordinate analysis a new assignment of the P2S62- frequencies is proposed.

1988 ◽  
Vol 43 (4) ◽  
pp. 326-330
Author(s):  
L. Ohse ◽  
M. Somer ◽  
W. Brockner

Abstract A normal coordinate analysis for the cage-like molecules α-P4S4, As4S4 and As4Se4 is performed, based on a simple initial force field with three numerical parameters and valence coordinates including redundancies. The force field is refined by adjusting the symmetry force constants to fit the observed frequencies. The final force field, potential energy distribution (PED), mean amplitudes of vibration and the standard thermodynamic functions from spectroscopic data are also given for the title compounds.


1986 ◽  
Vol 41 (10) ◽  
pp. 1233-1237 ◽  
Author(s):  
M. Parensen ◽  
W. Brockner

Na4P2Se6 has been prepared by elemental synthesis at high temperatures and characterized by vibrational spectroscopy. The vibrational frequencies of Na4P2Se6 are assigned on the basis of eclipsed P2Se64- conformers with D3h symmetry, those of Tl4P2Se6 on the basis of staggered P2Se64- units with D3d symmetry. A normal coordinate analysis has been performed for both conformers. The refined force field, potential energy distribution (PED), mean amplitudes of vibration an Coriolis coupling constants are given.


1985 ◽  
Vol 40 (7) ◽  
pp. 709-713 ◽  
Author(s):  
S. J. Cyvin ◽  
B. N. Cyvin ◽  
C. Wibbelmann ◽  
R. Becker ◽  
W. Brockner ◽  
...  

The title compound has been prepared by elemental synthesis at high temperatures and also by reaction of Na4P2S6 · 6H2O with CsCl in aqueous solution. Both reaction products have closely related vibrational spectra which are assigned on the basis of a P2S64- anion with perturbed D3d symmetry. A normal coordinate analysis has been performed using a force Field with 4 initial force constants. The refined force Field, potential energy distribution (PED), mean amplitudes of vibration and Coriolis coupling constants are given.


1978 ◽  
Vol 33 (6) ◽  
pp. 709-713 ◽  
Author(s):  
Wolfgang Brockner ◽  
Bjørg N. Cyvin ◽  
Sven J. Cyvin

Abstract A normal coordinate analysis was performed for some Cl5MOPCl3 molecules (M = Sb, Nb, Ta). The final force field in terms of a described set of symmetry coordinates is reported for Cl5SbOPCl3. The initial force field for Cl5SbOPCl3 was applied to calculate the vibrational frequencies of the Cl5NbOPCl3 and Cl5TaOPCl3 adducts. An assignment of the vibrational frequencies of the title compounds and the corresponding potential energy distribution terms are given for Cl5SbOPCl3 . For the Cl5SbOPCl3


1973 ◽  
Vol 27 (3) ◽  
pp. 209-213 ◽  
Author(s):  
John F. Jackovitz ◽  
Charles E. Falletta ◽  
James C. Carter

Infrared and Raman spectra for (K+) (CF3BF3−) have been obtained from 4000 to 50 cm−1. Spectral assignments were made on the basis of C3v symmetry using both 10B and 11B compounds. In addition, a normal coordinate analysis was performed to obtain the potential energy distribution of the normal modes. A Urey-Bradley type force field was used, and force constants obtained for the CF3 and BF3 groupings were compared to those in C2F6 and BF4−.


1974 ◽  
Vol 29 (12) ◽  
pp. 1898-1901 ◽  
Author(s):  
B. N. Cyvin ◽  
O. Gebhardt

Using spectroscopic data and structure parameters observed by electron diffraction, a normal coordinate analysis was performed for spiropentane. Harmonic force field, potential energy distribution and calculated mean amplitudes of vibration are reported. A very satisfactory agreement is found between observed and calculated mean amplitudes of vibration.


1969 ◽  
Vol 22 (6) ◽  
pp. 1123 ◽  
Author(s):  
K Ramaswamy ◽  
K Spinivasan

The potential energy constants of diacetylene and dicyanoacetylene were obtained by the method of ?characteristic set of valence coordinates? of Herranz and Castano. The values of the various interaction force constants were determined without any assumptions regarding force fields. The mean amplitudes of vibration for the various characteristic bonds were calculated by Cyvin's method. It is shown that the conventional set of symmetry coordinates, usually characterized by individual chromophores, leads to abnormally large values for the force constants in the case of dicyanoacetylene. Hence a different set of symmetry coordinates taking into account the whole unit of CC bonds has to be chosen to get a reasonable set of force constants.


1986 ◽  
Vol 41 (3) ◽  
pp. 549-552 ◽  
Author(s):  
B. N. Cyvin ◽  
S. J. Cyvin ◽  
M. Somer ◽  
W. Brockner

Normal coordinate analyses for the cage-like molecule ions P73-, As73- and Sb73- with C3 symmetry were performed, based on a very simple initial force field with three numerical parameters transferred from P4S3. FIR frequencies of Sb73- have been recorded. The force field was refined by adjusting the symmetry force constants to fit the observed frequencies. The final force fields were used to calculate the potential energy distribution terms (PED), the mean amplitudes of vibration and the first-order Coriolis coupling constants for the title molecule ions.


1996 ◽  
Vol 51 (4) ◽  
pp. 551-556 ◽  
Author(s):  
W. Preetz ◽  
B. Steuer

Abstract By reaction of [B6H6]2- with a solution of (SCN)2 in dichloromethane in the presence of solid KOH the hexaisothiocyanatodiborate anion [B2(NCS)6]2- is formed and can be isolated by fractionated crystallization. The crystal structure of (PNP)2[B2(NCS)6] has been determined by single crystal X-ray diffraction analysis; triclinic space group P1̄ with a=12,282(5), b=12,416(5), c=14,155(5)Å, a=68,36(5), β=70,59(5), γ=80,93(5)°.The [B2(NCS)6]2- anion reveals a staggered conformation with nearly local D3d symmetry and a B-B bond length of 1,73(2) Å. Using the crystallographic data a normal coordinate analysis has been performed. With a set of 12 force constants (e.g. fd(BB)=3,62, fd(BN)=4,21 mdyn/Å) a good agreement between observed and calculated frequencies for the 10B and 11B isotopomers has been achieved. The potential energy distribution on the force constants reveals strong vibrational couplings within the B2N6 framework.


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