ULTRAFAST DYNAMICS OF THE SOLVENT SOLUTE INTERACTION MEASURED BY FEMTOSECOND 4-WAVE-MIXING - LD690 IN N-ALCOHOLS

The fast dynamics of the oxazine dye LD690 in a series of n-alcohols a re investigated using several techniques, including linear absorption, resonance Raman, and the femtosecond three-pulse photon echo. The sys tematic variation in the dynamics as one goes from methanol to 1-penta nol can be explained in terms of processes stationary on the femtoseco nd timescale (inhomogeneous broadening) and a fast process with a solv ation correlation function M(t) = sech2(t/tau(C)) where tau(C) = 20 fs . The relative contributions of the fast and slow processes to the spe ctral broadening change as we increase the alcohol chain length.