Effective Operators and Spectroscopic Properties

Abstract

Perturbation summations that are characteristic of a wide range of spectroscopic problems are shown to be simply expressible in terms of effective operators involving the zero‐order states of the preponderant configuration. The methods developed involve the use of generalized unit tensor operators. Detailed applications to configuration‐interaction effects in $l^N$ configurations and to third‐order contributions to spectral intensities of ions in crystal fields are considered.