Thermal expansion of bismuth at low temperatures

Linear expansion coefficients are reported for bismuth down to 2°K. At the lowest temperature the anisotropy is considerable - α parallel /α perpendicular similar, equals 4. The Grüneisen parameter γ has a limiting value γ 0 similar, equals 1·8, a minimum value of 0·8 near 8°K and reaches approximately 1·2 at 80°K.