MATRICES Time-resolved CARS measurements of the vibrational decoherence of I 2 isolated in an Ar matrix

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 5 3–15. The temperature dependence of decoherence rates is negligible for v , 7 in the experimental range T 5 18–32 K. For a v 5 13, 14 superposition, the temperature dependence indicates dephasing by a 66 cm 2 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, a process which is characterized using polarized fields. The T ! 0 limit of dephasing is discussed. © 2003 Physics. @ DOI: #