Diatomics-in-molecules study of the photoabsorption spectra of Xen+ clusters

An extended diatomics-in-molecules model, employed previously in a theoretical study of the geometric and electronic structure of xenon cluster cations, Xen+ [P. Paška et al., Chem. Phys. 286 (2003) 237] is used to model the photoabsorption spectra of these clusters for a wide range of cluster sizes (n = 3-35). Both zero-temperature and non-zero temperature spectra are reported and several sampling schemes are used to simulate vibrational motion of atoms, including the constant temperature and constant energy Monte Carlo methods for non-zero temperatures, and zero-point wave-functions for normal harmonic vibrations of Xen+ for the zero temperature. The role of different structural isomers in photoabsorption experiments is also briefly discussed for selected cluster sizes. Our theoretical data are thoroughly compared with available experimental data. A fairly good agreement is achieved indicating a reasonable accuracy of the DIM modelling for the xenon cluster cations.