Vibrational excitations of arsine in the framework of a local unitary group approach

A description of vibrational excitations of pyramidal molecules in terms of the unitary group approach U(ν + 1) is presented. Based on the recent reformulation of this algebraic method the Hamiltonian is first expressed in the space of coordinates and momenta and thereafter translated into an algebraic realization in terms of the generators of the dynamical group Us(4) × Ub(4), where s and b stand for stretching and bending degrees of freedom, respectively. Fermi and number interactions are considered in the stretching-bending contribution of the Hamiltonian. This new approach provides in natural form the connection between the spectroscopic parameters and force constants. The analysis of the vibrational excitations of arsine is presented.