A set of force constants common for SiH3–X molecules

Abstract

A set of common force constants was obtained for the silyl group (SiH3–X) using as experimental data the frequencies from silyl cyanide (X=–CN), isocyanate (X=–NCO) and isothiocyanate (X=–NCS). Initial values of the force constants were obtained by ab initio methods, using three different levels of theory, Hartree–Fock, second order Moller–Plesset and Density Functional Theory. We have analysed the variation of the common block of force constants for the silyl group with respect to the nature of the X-substituent.