Modeling the solvation sites in rare-gas matrices with the simulated annealing Monte Carlo technique

The formation of solvation sites of rare-gas atoms (Rg = Ar, Kr) that trap the guest molecular systems is modeled using the simulated annealing Monte Carlo technique. As the guests, two molecular species are considered namely, the simplest hydrogen-bonded intermolecular complex (HF)2, and the radical SH in the excited electronic state. Both are important for investigations in the low-temperature matrices. The realistic potential energy surfaces for the simulations are constructed on the basis of spectroscopically parametrized functions for the constituting fragments and empirical solvent−solvent interaction potentials. It is shown that both examples give distinctively different pictures of the solvation sites. For the (HF)2@Arn clusters three types of solvation shells can be distinguished which correlate with the structures of pure argon clusters as well as with the structure in the bulk. For the SH@Rgn clusters no clear regularities are seen, and larger amounts of solvent atoms are needed to form the trapping cage.