Photoabsorption spectra of small mercury clusters: a computational study.

Photoabsorption spectra of small HgN clusters (N = 2-5) have been calculated using a diatomics-in-molecules interaction model and an atoms-in-molecules approach for transition probability calculations. Absorption cross-sections are provided over a broad range of photon energies, Ephot = 4.0-7.5 eV, as calculated for various cluster temperatures ranging between T = 0 K and T = 40 K. Quantum as well as temperature-induced delocalization of nuclear positions has been taken into account at various levels using classical and quantum (path-integral) Monte Carlo methods as well as sampling from the square of cluster vibrational ground-state wavefunctions. A thorough comparison of the calculated data with available experimental records is also provided.