High-Energy Vibrational Spectrum of Phosphine via a Non-Linear Model

A three-parameter dynamical model in non-linear quantum theory-the quantized discrete self-trapping equation-has been presented to calculate the stretching spectrum of PH bonds of phosphine at high-energy vibrational states until total vibrational quantum number n=7.The model calculations,which agree well with the experimental data and predict the centres of some overtone and combination bands with many excited quanta,show that PH₃ molecule has a remarkable local mode vibrational behaviour.