Photoabsorption spectra of small He-N(+) clusters (N=3, 4,10). A quantum Monte Carlo modeling

Abstract

Photoabsorption cross-sections have been calculated for He-N(+) clusters of selected sizes (N = 3, 4,10) over a broad range of photon energies (E-phot = 2 - 14 eV) and compared with available experimental data. Semiempirical electronic Hamiltonians derived from the diatomics-in-molecules approach have been used for electronic structure calculations and a quantum, path-integral Monte Carlo method has been employed to model the delocalization of helium nuclei. While a quantitative agreement has been achieved between the theory and experiment for He-3(-) and He-4(+), only qualitative correspondence is seen for He-10(+).