Vibration-inversion-rotation spectra of ammonia. A vibration-inversion-rotation Hamiltonian for NH 2D and ND 2H
The model Hamiltonian developed previously for ammonia NH 3 has been used to study the vibration-inversion-rotation energy levels of the isotopic species of ammonia NH 2D and ND 2H. In this model the inversion motion is removed from the vibrational problem by allowing the molecular reference configuration to be a function of the large amplitude motion coordinate. The ground state inversion-rotation energy levels of NH 2D and ND 2H have been calculated with the use of the zeroth-order inversion-rotation Hamiltonian, and the calculated transition frequencies have been compared with the experimental data.