Time-resolved CARS measurements of vibrational decoherence of I2 isolated in matrix Ar
M. Karavitis, D. Segale, Z. Bihary, M. Pettersson, and V.A. Apkarian
Department of Chemistry, University of California Irvine, CA 92697-2025, USA
Time-resolved coherent anti-Stokes Raman scattering is applied to prepare and interrogate vibrational coherences on the ground electronic surface of molecular iodine isolated in Ar matrices.
The coherence decay time shows a linear dependence on vibrational quantum numbers, for v = 3–15. The temperature dependence of decoherence rates is negligible for v < 7, in the experimental
range T = 18–32 K. For a v = 13, 14 superposition, the temperature dependence indicates
dephasing by a 66 cm–1 pseudo-local phonon, just outside the Debye edge of the solid. The accuracy
of the data is limited due to two-photon induced dissociation of the molecule, which process is characterized using polarized fields. The T → 0 limit of dephasing is discussed.PACS: 42.65.Dr - Stimulated Raman scattering; CARS (for Raman lasers, see 42.55.Ye) 67.80.-s - Solid helium and related quantum crystals