INTERNAL IONIZATION OF AR AND KR NOBLE-GAS CRYOCRYSTALS BY THE EXCITATION-ENERGY OF TRAPPED METASTABLE EXCITED ATOMS

Local metastable excited states are found in Ar and Kr cryocrystals wh en He gas-discharge products are trapped in the growing cryocrystals. These states are detected by ESR and are interpreted as being local me tastable excited np(5)(n + 1)s P-3(2) atomic-type states in Ar and Kr cryocrystals. The study showed that the yield of the P-3(2) excitation s in the above process decreases with increasing temperature. Analysis of the results allows the following explanation of the observed affec t to be given. Metastable excited He atoms from the He gas discharge a re trapped in the growing Ar or Kr cryocrystals and transfer their exc itation energy to the cryocrystal to form, in the process of internal ionization, a RG(+) ion and a free electron in the conduction band, wh ereupon the fast (10(-12) s) self-trapping reaction of a hole follows: RG(+) + RG --> RG(2)(+). Thereafter either the dissociative recombina tion reaction RG(2)(+) + e --> RG(2)* --> RG + RG*(P-3(2)) or recombi nation RG(2)(+) + e --> RG + RG to produce ground-state atoms could ta ke place, The former is likely at lower temperatures, and the latter a t higher temperatures when the vibrational relaxation rate of the RG() molecular ion increases and the mobility of free electrons in the co nduction band decreases. This is the reason for the observed temperatu re dependence.