Contact transformations in the mixed matrix-operator form: Effective rotational Hamiltonians for the excited vibrational states of symmetric top molecules

The effective rotational Hamiltonian for C3v or D3 molecules written in the basis of the vibrational wavefunctions |2±2> and |20> has been transformed by a rotational contact transformation such that the operators of thel-type interactions and of the Δl=0, Δ k≠0 interactions are eliminated from the first order terms of the expansion of the Hamiltonian in terms of the smallness parameter λ.