Equilibrium structure of chloroform

Abstract

The quadratic, cubic and semi-diagonal quartic force field of chloroform has been calculated at the MP2 level of theory employing a basis set of triple-ζ quality and in the frozen core approximation. A semi-experimental equilibrium structure has been derived from experimental ground state rotational constants and vibration–rotation interaction constants calculated from the ab initio force field determined in rectilinear normal coordinates. This structure is in excellent agreement with the ab initio structure calculated at the CCSD(T) level of theory using a basis set of quintuple-ζ quality and a core correlation correction. Experimental mass-dependent r m structures are also determined and are found to be much less accurate.