15min:

PAUL L. RASTON, RUDOLF LEHNIG AND WOLFGANG JÄGER, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G-2G2, Canada.

The pure rotation spectrum of carbonyl sulfide embedded in superfluid helium nanodroplets was measured in the frequency range from 4 to 15.5\nobreakspaceGHz. Four lines, corresponding to the J = 1-0, J = 2-1, J = 3-2, and J = 4-3 transitions were found. The line widths increase with J , and are about twice that of the corresponding rovibrational lines\footnoteS.\nobreakspaceGrebenev, M. Hartmann, M.\nobreakspaceHavenith, B. Sartakov, J.\nobreakspaceP. Toennies, and A.\nobreakspaceF. Vilesov, J. Chem. Phys. , \textbf112, 4485 (2000)., indicating faster rotational relaxation within the ground vibrational manifold. The comparison of the pure rotational spectrum with the microwave-infrared double resonance spectrum\footnoteS.\nobreakspaceGrebenev, M.\nobreakspaceHavenith, F.\nobreakspaceMadeja, J.\nobreakspaceP. Toennies, and A.\nobreakspaceF. Vilesov, J. Chem. Phys. , \textbf113, 9060 (2000). reveals that the double resonance measurement mainly probes rotational transitions within the upper vibrational manifold.