A local description of vibrational excitations of stibine in the framework of a unitary group approach

A local description of vibrational excitations of stibine 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. The Hamiltonian proposed is given in terms of curvilinear internal coordinates, where the stretching and bending modes are coupled with each other by Fermi resonances. In the new formulation a one to one correspondence with the Hamiltonian in configuration space is given, with the additional advantage that anharmonicities are taken into account from the outset. All experimental vibrational energies of 121SbH3 have been reproduced well with an rms deviation of 1.27 cm−1. From the spectroscopic parameters the force constants are obtained. A discussion comparing our approach with previous results using the same model is also included.