Knowledge Bank

The phosphorescence and phosphorescence-excitation spectra have been recorded for benzene and benzene-$d6$ in krypton and xenon lattices at $20\circ K$. The spectra were compared to those in argon lattices. Several sites of benzene in the rare gas hosts have been seen in the spectra and a group theoretical approach has been used to relate the vibronic structure in the phosphorescence spectrum to the local environment of the molecule. Some site synmetries have been assigned in Ar, Kr, and Xe lattices and the most probable transition mechanisms will be discussed for these sites. Phosphorescence decays were measured in each individual site and it is found that there is no deuterium effect in Kr or Xe.