Charged chromophoric units in protonated rare-gas clusters: A dynamical simulation

The process of protonation in small rare-gas clusters and the study of the most stable structures with He and Ar clusters containing a positively charged hydrogen atom are examined by performing both energy optimization calculations and simulated temperature annealing dynamics. The interaction is modelled via gradient-corrected density functional theory effective potentials and the nuclear dynamics is treated classically. The present results clearly show the presence of a linear symmetric chromophore, He2H+, in the case of helium clusters, while the argon cluster calculations provide evidence for the existence of a more tightly bound ArH+ as the main chromophoric molecular core. Such results confirm earlier findings from quantum chemistry calculations for helium and provide for the first time a realistic modelling for argon clusters