Semiclassical quantization of the vibration-rotation problem

A semiclassical quantization of rigid bender H2O with a single bending vibration coupled to three dimensional rotation is presented. Angular momentum conservation reduces this problem to two degrees of freedom. An efficient new algorithm is developed for EBK semiclassical quantization in two dimensions, and a tunneling approximation used to generate asymmetry splitting. This technique reproduces to within 1% the level shifts due to vibration-rotation interaction for j=3,10 and nv from 0 to 3 and is successful where the usual approximate quantum (centrifugal distortion) treatment of these interactions fails.