Absorption and emission spectroscopy of perylene (C20H12) isolated in Ne, Ar, and N-2 matrices

The electronic absorption and emission spectra of perylene (C20H12) isolate d in rare gas (Ne, Ar) and N-2 matrices are presented. While the electronic band systems show, in all matrices, the same fundamental frequencies as th ose observed in gas-phase jet experiments, the spectra in Ar and N-2 matric es exhibit much more spectral structure. The observed structure points to s trong host-guest interactions and provides new insight into the low frequen cy modes of perylene. In particular, the spacing observed at 11 and 16 cm(- 1) in the S-0 and S-1 states, respectively, might be attributed to the gera de accordion mode of perylene. This mode, which has never been observed dir ectly in jet experiments, could be induced into activity in solid matrices. (C) 1999 American Institute of Physics. [S0021-9606(99)00915-0].