Electronic Spectral Shifts and Linebroadening of Heteroclusters

In this paper we report on molecular dynamics simulations of the lineshapes of the absorption spectra of perylene Ar_n heteroclusters (n = 2–22), which rest on the spectral density method in conjunction with the excited‐state potential modelling scheme. Inhomogeneous semiclassical absorption lineshapes were calculated by averaging of microcanonical spectra over the accessible phase space region. The size dependence and isomer specificity of the spectral shifts and spectral linewidths were elucidated, with the spectral shifts providing a powerful tool for the identification of structural isomers. Some information on isomerization dynamics was inferred from the temperature dependence of the linewidths, which mark the onset of correlated surface motion for (5|0) and (5|5) heteroclusters, as well as the onset of 2D ⇄ 3D isomerization and side crossing for (22|0) heteroclusters.