Nuclear Quadrupole Resonance and the Electric Field Gradient in Metallic Indium

The nuclear quadrupole resonance in metallic indium has been followed continuously from 4.2°K to 390.2°K and two sources of field gradient have been investigated. One of these is the usual "ionic" model involving point ions in a uniform background charge density. The contribution from this source has been calculated by a new method to seven figures at three representative $\frac{a}{c}$ ratios; from these data the ionic field gradient in indium at any submelting temperature can be inferred.