Pseudo-exact Force Constants for Tetramethyls of Group IVA Metals and Molecular Force Fields for Some Tetrahedral Molecules or Ions

Abstract

Abstract Recently reported Coriolis constants of tetrahedral tetramethyls of group IVA metals from the vapour phase IR spectra have been used to determine the pseudo-exact force constants with the aid of the point mass model. The symmetrized force constants for tetramethyls of group IVA and some tetrahedral molecules and ions have also been computed following thhe L-F approximation method. The results are compared with exact or pseudo-exact force constants and with those force constants obtained from different approximation methods. The validity of the method has been tested.