15min:

JEREMY M. MERRITT, GARY. E. DOUBERLY AND ROGER E. MILLER, Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.

We report high-resolution IR-IR double resonance spectra of the ₁ fundamental (C-H stretch) of HCCCN solvated in superfluid helium droplets. Double resonance schemes of this type are highly effective in ``tagging'' molecules whose spectral broadening is due in part to static inhomogeneous broadening. The timescale of pump and probe is long compared to vibrational relaxation to the droplet, so that a hole can be burned in the helium droplet size distribution. Experiments of this type remove the contribution to the linewidth from the droplet size distribution and allow for a more in-depth analysis of a solvated molecules' local environment.