ABSTRACT
In order to estimate the intensity of radiation and in other applications, it is useful to obtain closed expressions for sums of the form () Σ k ω kn p | x kn | 2 ω kn = E k − E n ħ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429493645/749bab20-4a79-4f5a-8c66-d9e9a36a87b9/content/eq970.tif"/>
