An accurate analytic approximation to the non-linear change in volume of solids with applied pressure

An accurate analytic expression for the non-linear change of the volume, Delta V/V 0 , of a solid as a function of applied pressure, P, is of great interest in high-pressure experimentation. The authors have found that the two-parameter analytic expression, ( Delta V/V 0 )=(1/ alpha )ln(1+ beta P), fits the experimental Delta V/V 0 data, to within a few per cent over the entire experimentally attainable pressure range. Results are presented for 24 different materials including metals, ceramic semiconductors, polymers, ionic and rare-gas solids.