Accurate analytic expectation values for an anharmonic oscillator using the hypervirial theorem

Abstract

An analytic recursion relation for the calculation of expectation values of any power of the internuclear displacement from equilibrium in an arbitrary vibration‐rotation level of ¹Σ‐state diatomic molecules is derived via an iterative solution of the hypervirial theorem. Explicit results, more accurate than those previously published, are given for the first six powers of the displacement along with numerical results for H₂ and HCl to illustrate the accuracy obtained.