Calculation of quadrupole interactions in the high pressure phase of $\beta {\text{ - }}$gallium metal

Abstract

Electric field gradient q and quadrupole interaction frequency $\nu$ calculated at 256.7 K in the high pressure phase (orthorhombic) of $\beta {\text{ - }}$ Ga metal are reported. The results are: q=+0.251 atomic units (au), $\nu$=5.479 MHz. These are compared with results from experiment and previous calculation available for the monoclinic phase of $\beta {\text{ - }}$ Ga metal at normal pressure. The results from the previous calculation at 248 K are: q=-0.250 au and $\nu$=5.318 MHz. The result from experiment extrapolated to 256.7 K is: $\nu$=4.871 MHz. The sign reversal of the calculated q is attributed mainly to the change of point symmetry of the lattice from the orthorhombic to monoclinic. That the interaction frequency in high pressure phase is higher than experiment may be partly due to the increase of pressure and partly to the structural phase change.