Perylene–rare-gas heteroclusters. I. Electronic spectroscopy

Publisher Website
Google Scholar
Abstract
In this paper we report on the electronic two-photon two-color near threshold spectroscopy of mass-resolved perylene⋅Arn (n=1–45), perylene⋅Krn (n=1–35), perylene⋅(N2)n (n=1–12), and perylene⋅(CH4)n (n=1–10) heteroclusters. The S0→S1 inhomogeneously broadened spectra of perylene⋅Arn (n=1–6) and perylene⋅Krn (n=1–4) exhibit resolved spectral features, which were assigned on the basis of experimental combination rules and polarizability relations to the electronic origins of distinct two-sided and one-sided structural isomers. Larger perylene⋅An (A=Ar, Kr; n=6–10) heteroclusters exhibit an ‘‘abnormal’’ specific size dependence of the red spectral shifts, which decrease with increasing n and reach a local minimum at n=8. Similar characteristics of the red spectral shifts are exhibited for perylene⋅(N2)n and perylene⋅(CH4)n (n=4–8) heteroclusters. This abnormal size dependence of the spectral shifts is attributed to the dominance of one-sided single-layered and double-layered structural isomers in this cluster size domain. On the basis of the comparison between the spectroscopic data and molecular dynamics simulations of the absorption line shapes we have obtained a quantitative description of isomer-specific structures for n=2–6, a semiquantitative description of the abnormal size domain for n=6–10 (due to the dominance of one-sided structures with the abundance of two-layered structures increasing at higher n), the prevalence of one-sided structures for n=16 and n=22, and the realization of two-sided multilayered structures at n=45.