dc.creator Salem, Lionel en_US dc.date.accessioned 2006-06-15T13:09:29Z dc.date.available 2006-06-15T13:09:29Z dc.date.issued 1961 en_US dc.identifier 1961-K-6 en_US dc.identifier.uri http://hdl.handle.net/1811/8109 dc.description $^{\dagger}$The research was made possible by support extended Harward University by the Office of Naval Research under ONR Contract Nom 1866, Task Order XIV. en_US dc.description Author Institution: Mallinckrodt Chemical Laboratory, Harvard University en_US dc.description.abstract A new sum-rule is derived for certain sums of the form $\Sigma^{\prime}_{i}\frac{<0|A_{op}.|i>\;}{E_{i}-E_{o}}$ The result is exact and involves no approximations such as energy averages, etc. The rule is applied to the study of two cases where the Hellmann-Feynman theorem yields incorrect forces if unperturbed wave functions are used to calculate the electron density: a) the neutral atom in a uniform electric field; b) the London-van der Waals interaction of two neutral atoms. en_US dc.format.extent 64270 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title A NEW SUM RULE AND SOME SIMPLE $APPLICATIONS^{\dagger}$ en_US dc.type article en_US
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