Molecular vibrational analysis of tetramethyl compounds of fourth group elements

Abstract

The n a t u r e of molecular Vibrations has been malysed f o r (C&)4 M compounds, M = c, S i , CB, Sn and Pb t h e o r e t i c a l approach. The forms of &-vibrRtions have been d i s c u s s e d using the r o p e r t i e s of L m a t r i c e s and experimental C o r i o l i s coupling constant dsta. !he o v e r a l l force f i e l d available so f a r has been c r i t i c a l l y analysed following I s o t o n i ' s c r i t e r i o n . The r e s u l t s h ve a l s o been discussed i n the l i g h t of kinematic Coupling ( T = Gar/ d&%d-), v i b r a t i o n a l c o n s t a n t s of t e t r a h e d r a l molecules, (M-C) bonding and compliance constants. It hes been observed t h a t for tetramethyl compounds w i t h l i g h t e r c e n t r a l mass (M), any anproximation nethod would give less satisfactory r e s u l t s due t o excessive kinematic coupling m d hence for neo-pentane the "point-mass model" is less valid.