SPIN COUPLING AND MEMORY EFFECTS IN THE OPTICAL CYCLE OF FH CENTERS INVOLVING ELECTRON VIBRATIONAL-ENERGY TRANSFER

Spin-coupling and spin memory effects of F(H)(OH-) and F(H)(CN-) centers have been studied in various hosts at 2 K. The spin-memory loss epsilon, i.e. the probability of spin-flip during a complete electronic excitation and relaxation cycle, has been determined. The main result is a strong increase of the spin-memory loss epsilon for F(H)(CN-) in CsCl and CsBr compared to F centers, while epsilon remains nearly unchanged (only a slight decrease) for F(H)(OH-) centers in KCl and KBr. First attempts will be made to explain these spin-memory loss results in correlation to the electron relaxation and electron-vibrational energy transfer processes occurring in the same optical cycle.