SPECTRA AND RELAXATION OF HG ATOMS AND MOLECULES IN LOW-TEMPERATURE MATRICES .2. H2O/AR AND NH3/AR MATRICES

The absorption, excitation and emission spectra are recorded for Hg.NH3 and Hg.H2O/D2O complexes and Hg(NH3)n and Hg(H2O)n/(D2O)n Clusters in argon and krypton matrices. The excited states correlated to the P-3(1) state of Hg were selectively pumped. The P-3(1) --> P-3(0) nonradiative relaxation of HgM (HgM(n)) systems is so efficient that the P-3(1) --> S-1(0) emission is completely quenched. The excited systems decay by the P-3(0) --> S-1(0) emission, this radiative transition being weakly allowed. As evidenced by the broad band exciplex emission, these systems are strongly bound in their excited states correlated to the P-3(0) state of Hg, while the interaction of ground-state Hg atoms with water and ammonia is weak. The existence of specific Hg ... (H2O)n sites with the emission spectra involving a coupling between electronic transition in Hg and intramolecular modes of the H2O (D2O) molecule is reported.