Knowledge Bank

“Perturbation calculations involving vibration-rotation interactions are usually simplified by subjecting the Hamiltonian to a contact transformation, $H\prime =THT-1$, with $T=\exp (i\lambda S)$. The same technique may be useful in may be useful in many simpler problems. As a detailed example an S function is exhibited for the slightly asymmetric rotator, and analytical expressions are given for energy coefficients of the type tabulated by $Schwendeman.1$”