Off-diagonal matrix elements and sum rules for the Coulomb and isotropic oscillator systems are obtained from a study of relations between the off-diagonal matrix elements of a general recursion relation.
MAVROMATIS, HARRY A. (2002) "Off-diagonal Matrix Elements and Sum Rules involving Coulomb and Isotropic Oscillator Functions," Turkish Journal of Physics: Vol. 26: No. 4, Article 1. Available at: https://journals.tubitak.gov.tr/physics/vol26/iss4/1