MATRIX ISOLATION OF EXCITED METASTABLE ATOMS AND ENERGY TRANSFER IN NOBLE-GAS CRYOCRYSTALS

$^{1.}$ R. A. Zhitnikov. Yu-A-Dmitriev and M. E. Kaimakov. Sov. Phys JETP 72, 1009(1991) $^{2.}$ R. A. Zhitnikov, Yu-A-Dmitriev and M. E. Kaimakov. Sov. J. Low. Temp. Phys. 18, 532(1992).Author Institution: A. P. loffe Physico---Technical Institute, St. PetersburgThe original experimental technique and setup have been developed which makes it possible to detect and study by $ESR^{1,2}$ local unstable excited states in noble-gas cryocrystals. Very recently, we have discovered by ESR a new effect - formation in Ne cryocrystals of local excited states as a result of a He gas discharge product trapping in the growing Ne crystal. It is important that no excited states appeared in Ar and Kr cryocrystals under the action of the He gas discharge. It may be supposed that the effect observed in Ne is the result of the quasi-resonance transfer of excitation energy from the metastable $2^{3}S_{1}$ He atoms trapped from the gas discharge in Ne cryocrystal to the X-exciton band of the Ne crystal followed by the self-trapping of the exciton, its decay, and formation of the localized in fee Ne crystal $^{3}Pz$ Ne atom observed in the experiment. $^{3}P_{2}$ neon atom, having a large radius, causes its surroundings to shift outwards and the Ne crystal lattice to rearrange itself in the vicinity of this atom. We have recorded a temperature dependence of the $^{3}P_{z}$ state formation probability in Ne crystal and obtained the activation energy for the metastable $2^{3}S_{1}$ He atom to transfer its excitation energy to the Ne crystal X-exciton band. This energy is about 0.001 eV