Ultrafast photoinduced processes in indole-water clusters

Applying femtosecond laser pulses at the wavelength of 250 nm the photoinduced processes in indole(H2O)(n) and (D)-indole(D2O)(n) clusters have been studied. An ultrafast (similar to50 fs) decay of the initially excited pipi* state is tentatively attributed to the internal conversion to the dark pisigma* state. Subsequent processes are characterized for n = 1, 2 by a single-exponential signal decay on the ps time scale, while for larger clusters (n greater than or equal to 3) no significant time dependence is observed. The strong differences with respect to the photophysics of indole(NH3)(n) clusters are discussed. (C) 2003 Published by Elsevier Science B.V.