Summary: 5372 J. Phys. Chem. 1991, 95, 5372-5374
Photodynamics of (Cl& Clusters Trapped in SolM Krypton
G. J. Hoffman and V. A. Apkarian*"
Department of Chemistry, University of California, Imine, California 92717 (Received: March 11, 1991;
In Final Form: May 6, 1991)
Emission and excitation spectra of C12clusters isolated in solid Kr, matrix and freestandingcrystal, are reported. A brooldened
emission progression in the crystalis ascribed to dimeric A' -X;additional molecular aggregatesare evident in the matrix.
The dimericA' state relaxes radiatively with a lifetime identicalwith that of the monomer (T = 49 f 1 ms), whereas the
B state undergoes nonradiativerelaxation on a time scale that competes with predisswiation. A significantdifference in
intermolecularbinding between excited and ground statesis inferred. The clustersdo not undergo permanent dissociation
at an excess energy of 1.5 eV.
Molecular clusters trapped in rare-gas solids provide a fasci-
nating conceptual model for the investigation of molecular dy-
namics in tightly oriented systems. Many-body interactions,
intermolecular potentials, energy transfer, and biomolecular re-
action dynamics are possible targets of such investigations.
Spectroscopic and dynamical information obtained from such
studies should also be complementary to the related, well-estab
lished field of cluster dynamics in molecular beams. In the lit-
erature of matrix isolation spectroscopy, there is a wealth of