Theoretical calculations of pressure-induced blue and red shifts of spectra of ruby

On the basis of the concept of expansion of the electron radial wavefunction under compression, using expressions for B, C and Dq as functions of the linear compression ratio kappa and taking into account the configuration interaction (through the Coulomb interaction) and the interaction (through the trigonal crystal field) between t 2g 3 2 E g and t 2g 3 2 T 1g mixed states, the authors calculate theoretically the pressure-induced shifts of the R, R' and B lines and the U and Y broad bands of the spectra for ruby. The results agree well with all the experimental data over a wide pressure range.