THE METASTABLE NE(P-3(2)) AND N(D-2) ATOMS IN CORES OF SOLITARY AND STICKING HELIUM CLUSTERS HELIUM SURROUNDING AND HEAVY NEIGHBOR INFLUENCE

The fluorescence excitation spectra oi metastable P-3(2) Ne atoms in superfluid helium have been studied for the first time. Ne spectral lines show a surprisingly small broadening and shift. We have also studied emission spectra and decay times related to the strongly forbidden N(D-2 --> S-4) transition in the impurity-helium solid phase (IHSP) containing metastable N atoms, N-2 molecules and - in some cases - rare gas atoms (Rg = Ne or Kr). We have shown that the central cores of solid He clusters correspond to single metastable N*(D-2) atoms or to N*-N-2 and N*-Rg pairs as well as to triple N*-N-2-Rg and exciton-like N*Rg(n), complexes, as evidenced by their luminescence spectra.