LUMINESCENCE SPECTROSCOPY OF ATOMIC ZINC IN RARE-GAS SOLIDS .1.

Steady-state and time-resolved luminescence spectroscopy of atomic zin c isolated in thin film samples of the solid rare gases, prepared by t he cocondensation of zinc vapor with argon, krypton, and xenon has bee n recorded at 6.3 K using synchrotron radiation. Pairs of emission ban ds result from photoexcitation of the singlet 4p P-1(1)<--4S S-1(0) re sonance transition of atomic zinc, even in annealed samples. In Zn/Ar the pair of emission bands were observed in the uv at 218.9 and 238 nm and for Zn/Xe in the near-uv at 356 and 399 nm. For the Zn/Kr system two emission bands were observed in the uv region at 239.5 and 259 nm but in addition, a weaker band was present in the near-uv at 315.6 nm. In a given annealed rare-gas host, the excitation profiles recorded f or all the emission bands are identical, exhibiting the threefold spli tting characteristic of Jahn-Teller coupling in the triply degenerate excited P-1(1) state. These excitation profiles are identified as the solid phase equivalent of the 4p P-1(1)<--4s S-1(0) resonance transiti on of atomic zinc occurring at 213.9 nm in the gas phase. Based on the ir spectral positions and temporal decay characteristics, the emission bands observed in the uv and near-uv spectral regions have been assig ned as the singlet and tripler transitions, respectively, of atomic zi nc. The origin of the pairs of emission bands is ascribed to the Jahn- Teller coupling between noncubic vibronic modes of the lattice and the excited 4p orbital of the P-1(1) state of atomic zinc, resulting in t he coexistence of two energy minima. In Zn/Ar, the effects of slow vib rational relaxation in the excited singlet state were evident in the r elative intensities and temporal decay profiles of the pair of emissio n bands. Specifically, the lower energy emission band was favored with excitation of the highest energy component of the threefold split Jah n-Teller absorption band, while the higher-energy emission was favored with excitation of the lowest-energy component. The intensity of the tripler state emission was observed to be enhanced in the heavier rare gases, being completely absent in Ar, weak in Kr, and the only emissi on observed in Xe. (C) 1997 American Institute of Physics.