Site symmetry and effective Hamiltonians for H2X molecules in the local mode limit

摘要

Abstract: The effective rotational Hamiltonian for the stretching modes of H$-2$/@X molecules have been analyzed on the base of the two conceptions: site-symmetry and linked groupings of vibrational rotational interactions. The site-symmetry of the effective Hamiltonian for the region of (v$-1$/, v$- 3$/@) dyad of H$-2$/@X molecules at the condition m$-H$/ $VLS m$-x$/ is reduced to C$-s$/ symmetry, as compared with C$-2$/@V symmetry of the initial Hamiltonian. For the first time for H$-2$/@X molecule with strong Coriolis-type accidental resonance it had been shown that the parameters of effective Hamiltonian depend on groupings of vibrational- rotational interactions. This dependence from weak via middle to strong resonances has the trend to decrease. For H$-2$/@S molecule at the local mode limit, the effective Hamiltonian for Coriolis-type resonance don't depend on the groupings of initial Hamiltonian expansions. Two ways of experimental energy levels assignment for some vibrational polyads of H$-2$/@S molecule, based on the symmetry reduction conception have been presented.!11