Theory of the Tunneling Excitation of OH Ions in the NaCl Crystal

A theory of the response to external perturbations in the off-center tunneling system is given, and applied to NaCl:OH. Adjustable parameters entering the unperturbed off-center potential are fixed by referring to spectroscopic data. With this potential, calculations are made on: (1) temperature dependence of the optical absorption spectra and elastic anomaly, (2) electric field and stress dependence of the tunneling levels and optical transition probabilities, and (3) temperature dependence of the electric susceptibility. The results explain successfully the corresponding experimental data.