We present resonant two-photon two-color photoionization (R2P2CI) spectra of a series of Aniline-Ar, complexes (n --1 -6). An apparently anomalous blue shifted spectra for An-Ar 3 is explained by a modified spectral shift additivity rule which assigns different shifts to different relative positions of the Ar with respect to aniline. Evidence is presented for the existence of several isomers of clusters with n > 2. It is shown that, by changing the nucleation conditions, it is possible to control the relative populations of the various isomers.

Hybrid quantum/classical simulation and kinetic study of the vibrational predissociation of Cl 2 Ne n (n=2,3) I 0 2 , and 1 0 1 , of the S 1 ←S 0 transition, exhibit lifetime broadening with respect to transitions to the corresponding states in the aniline monomer. The dispersed emission spectra taken under excitation of the same three vibronic bands give access to both the distribution of aniline monomer states produced by vibrational predissociation of the complex and to the rates at which this dynamics proceeds. The overall results are discussed in a consistent way, with emphasis being given to the role of the coupling between the intramolecular and the intermolecular vibrational states. In the case of I 0 2 excitation, it is shown that this coupling is reflected in the shape of the van der Waals wavefunction, as accessed through the analysis of the high resolution spectra ͓M. Becucci, G. Pietraperzia, N. M. Lakin, E. Castellucci, Ph. Bréchignac, Chem. Phys. Lett. 260, 87 ͑1996͒.͔.