Multistate Isomerization of Size-Selected Clusters

Abstract
The electronic spectra of mass-specific dichloroanthracene · KrN clusters were interrogated by resonant two-photon two-color ionization. A novel effect of abrupt spectral line narrowing with increasing cluster size at N=17 was observed, which signals the nonrigid-to-rigid, collective, three-dimensional, multistate isomerization in the heterocluster.