Frequency shift analysis of matrix isolated impurities

A method is presented for calculating the shift of an impurity spectrum in the rare‐gas solids Ar, Kr, and Xe. The intermolecular potentials are approximated by Lennard‐Jones potentials for this purpose, the parameters of which are obtained from specially chosen combination rules. An expression for the lineshift in terms of these parameters, the host geometry, and the polarizability of the species is derived. If certain variables in this expression are appropriately grouped together there exists a linear relationship which is graphically demonstrated for various examples. It is shown that the consideration cannot be extended to neon as a host matrix.