Least‐Squares Calculation of OVFF Force Constants for XY4 Tetrahedral Molecules

1955 ◽  
Vol 23 (9) ◽  
pp. 1727-1727 ◽  
Author(s):  
William S. Horton
Keyword(s):  
Least Squares ◽  
Force Constants ◽  
Tetrahedral Molecules

Force Constants of Tetrahedral Molecules

1958 ◽  
Vol 28 (3) ◽  
pp. 514-515 ◽  
Author(s):  
C. W. F. T. Pistorius
Keyword(s):  
Force Constants ◽  
Tetrahedral Molecules

Ein Iterationsverfahren zur Berechnung von Kraftkonstanten aus Grundschwingungsfrequenzen

1970 ◽  
Vol 25 (8-9) ◽  
pp. 1274-1280
Author(s):  
W. Hüttner
Keyword(s):  
Least Squares ◽  
Force Constant ◽  
Vibrational Frequencies ◽  
Force Constants ◽  
Normal Equations

Abstract A method for the adjustment of force constants from vibrational frequencies is presented. It re-presents an alternative to the various types of least-squares procedures which are widely used in force constant calculations, and avoids some of the well-known divergence difficulties which may occur in such least-squares iterations. Solving a system of normal equations is replaced by two simpler operations which cannot become ill-conditioned by singularities. The method applies preferably to cases where the number of excess data is small or zero.

Least squares refinement of valence force constants in crystal dynamics

1973 ◽  
Vol 26 (2) ◽  
pp. 425-433 ◽  
Author(s):  
Paola Bosi ◽  
Riccardo Tubino
Keyword(s):  
Least Squares ◽  
Force Constants ◽  
Valence Force ◽  
Crystal Dynamics

Tetraquecksilbermethane, II [1]Tetrakis(halogenoquecksilber)-methane C(HgX)4 (X = F, Cl, Br und I): Synthesen und Schwingungsspektren / Tetramercurimethanes, II [1]Tetrakis(halomercuri)methanes C(HgX)4 (X = F, Cl, Br und I): Syntheses and Vibrational Spectra

1979 ◽  
Vol 34 (3) ◽  
pp. 390-395 ◽  
Author(s):  
Dietrich Breitinger ◽  
Wilfred Morell ◽  
Knut Grabetz
Keyword(s):  
Vibrational Spectra ◽  
Hydrofluoric Acid ◽  
Force Constants ◽  
The Other ◽  
Other Hand ◽  
Highly Sensitive ◽  
Symmetry Species ◽  
Complete Series ◽  
Tetrahedral Molecules

Abstract The complete series of tetrakis(halomercuri)methanes C(HgX)4 (X = F, Cl, Br and I) was prepared by metathesis of tetrakis(acetoxymercuri)methane and aqueous hydrofluoric acid and solutions of halides (Cl-, Br-, and I-), respectively. All compounds are insoluble in most common solvents, but partly soluble in dimethylsulfoxide. Complete vibrational spectra indicate more or less ideally tetrahedral molecules C(HgX)4 in all cases. The originally triply degenerate valence vibrations of the CHg4 entities and the force constants for the C-Hg bonds show distinct correlations with the electronegativities of the halides X. On the other hand the totally symmetrical valence vibrations of CHg4 were found to be highly sensitive to variations in X, mainly due to coupling with the valence vibrations of the Hg-X-groups of the same symmetry species. Some analogies in the vibrational behaviour of the CHg4 fragments and of the isosteric NHg4 core in tetramercurioammonium complexes were observed and discussed.

Vibrational Spectra and Force Constants of Symmetric Tops VL [1] Spin Flip Raman Laser Spectra and Rotational Analysis of (v1 + v2) of CF3Cl and CF3Br

1985 ◽  
Vol 40 (3) ◽  
pp. 233-238 ◽  
Author(s):  
M. K. Haj-Abdallah ◽  
H. Pascher ◽  
H. G. Häfele ◽  
A. Ruoff ◽  
H. Essig
Keyword(s):  
Ir Spectra ◽  
Least Squares ◽  
Vibrational Spectra ◽  
Least Squares Method ◽  
Raman Laser ◽  
Force Constants ◽  
Rotational Analysis ◽  
Spin Flip ◽  
Isotopic Abundances ◽  
Parallel Band

The IR spectra of gaseous CF3Cl and CF3Br with natural isotopic abundances have been investigated in the region 1830-1900 cm-1 with a resolution of 0.01 cm-1 or better using a Q-switched spin-flip Raman laser (SFRL). Both J and K structure of the parallel band (v1 + v2) have been resolved partly for both isotopomers of CF3Cl and CF3Br, respectively. The analysis has been performed by the usual least squares method. Additionally the J clusters of some hot bands have been observed and analyzed.

Calculation of internal valence force constants for XY4 (Td) tetrahedral molecules

1992 ◽  
Vol 271 (3) ◽  
pp. 237-249 ◽  
Author(s):  
M. Fernández Gómez ◽  
J.J. López González ◽  
N. Rajamanickam ◽  
E. Martínez-Torres
Keyword(s):  
Force Constants ◽  
Valence Force ◽  
Tetrahedral Molecules

Intramolecular Force Field of some Tetrahedral Molecules and Ions

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1213-1216 ◽  
Author(s):  
B. B. Srivastava ◽  
A. K. Dublish ◽  
A. N. Pandey ◽  
A. K. Mithal
Keyword(s):  
Force Field ◽  
Relative Stability ◽  
Force Constants ◽  
Kinetic Constants ◽  
Lennard Jones Potential ◽  
Jones Potential ◽  
Valence Force ◽  
Valence Force Field ◽  
Lennard Jones ◽  
Tetrahedral Molecules

Abstract The orbital valence force field (OVFF), and the Urey-Bradley force field (UBFF) have been employed to calculate the force constants for six molecules and ions (AlCl4-, AlBr4-, AlI4-, Til4- , Os16O4 , and Os18O4). The results have been discussed in the light of the relative stability of the bonds. The applicability of the Lennard-Jones potential is also examined. The kinetic constants have been computed and the results have been correlated with the corresponding force constants.

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