The Shift and Splitting of the F‐Absorption Band in Alkali Halide Crystals by Application of Uniaxial Pressure

Abstract

Abstract Application of uniaxial pressure results in splitting and dichroism of the F‐band and a shift to higher energies. The effect is examined, with the compression parallel to the [100] direction, in the following substances: NaF, NaCl, KCl, RbCl, KI. For NaCl, measurements are also made with the compression parallel to the [110] and [111] directions. By symmetry considerations a theory is derived which gives the shift and splitting for arbitrary directions of pressure and polarization, including the hydrostatic case. The relation of three parameters employed in this theory to the elastic constants and the energy levels of the F‐centre is discussed.