Infrared signatures for isomerization and melting in inhomogeneous van der Waals clusters

Molecular dynamics simulations are combined with a model for predicting the perturbed infrared spectrum of SF6 in rare gas clusters and used to generate synthetic spectra for a range of cluster isomers and effective temperatures. It is shown that the perturbed infrared spectrum of a vibrationally degenerate chromophore solvated in a cluster can be an incisive tool for determining the number, arrangement, and dynamical state of the solvent particles surrounding the chromophore. The simulations described herein also draw attention to a kind of melting behavior in which the time scale of the ‘‘measurement’’ directly affects the perception of whether the system is liquidlike or solidlike.