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 s uperfluid helium have been studied for the first time. Ne spectral lin es show a surprisingly small broadening and shift. We have also studie d emission spectra and decay times related to the strongly forbidden N (D-2 --> S-4) transition in the impurity-helium solid phase (IHSP) con taining metastable N atoms, N-2 molecules and - in some cases - rare g as atoms (Rg = Ne or Kr). We have shown that the central cores of soli d 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*R g(n), complexes, as evidenced by their luminescence spectra.