NEW OPERATORS FOR ELECTRONIC DENSITY CALCULATION .1. DERIVATIONS AND FORMAL ANALYSIS

The electronic charge and spin density at any point in space are reexp ressed in terms of the expectation values of any member of a general c lass of global operators. For practical use with approximate wave func tions, two particular choices of operator are made that should provide advantages for the difficult case of density evaluation at a nucleus. Formal properties of these operators are derived and discussed in det ail. Certain serious difficulties known for the behavior of the global operator previously introduced by Hiller, Sucher, and Feinberg are am eliorated in the new formulations. (C) 1996 American Institute of Phys ics.