CORE MODEL FOR SINGLE-CENTER CALCULATIONS OF ELECTRIC FIELD GRADIENTS . APPLICATION TO LID

The nuclear quadrupole coupling constant provides an example of a property which is sensitive to the form of the electronic wavefunction in the region of the quadrupolar nucleus. A method is discussed in which the wavefunction is separated into a core and a portion surrounding the quadrupolar nucleus. This latter portion of the wavefunction is determined by means of a single-center expansion. Calculations of the electric field gradient at the deuteron in LiD are presented. The dependence of the calculations on the core and on the position of the expansion center is studied. The results are in good agreement with experiment and more elaborate calculations.