Vol. 12, issue 02, article # 6

Abstract:

The problem of calculation of the sextic centrifugal distortion constants is considered within the framework of the "expanded local mode approach" for XY₂ (C_2v), XY₃ (C_3v), and XY₄ (T_d) molecules with relatively heavy X nucleus. Some conditions imposed on the structure and dynamic characteristics of molecules of this type allow significantly simpler derivation of analytical expressions for parameters of the effective rotational Hamiltonian. The simple expressions can be thus obtained for the sextic centrifugal constants. As an illustration, the corresponding values of the centrifugal constants are calculated using these expressions for such molecules as H₂Se, H₂S, AsH₃, SbH₃, CH₄, SiH₄, and GeH₄. The correspondence between the calculated and experimental values is demonstrated.