Adsorption of molecular hydrogen on coronene with a new potential energy surface

Benchmark interaction energies between coronene, C24H12, and molecular hydrogen, H-2, have been computed by means of high level electronic structure calculations. Binding energies, equilibrium distances and strengths of the long range attraction, evaluated for the basic configurations of the H-2-C24H12 complex, indicate that the system is not too affected by the relative orientations of the diatom, suggesting that its behavior can be approximated to that of a pseudoatom. The obtained energy profiles have confirmed the noncovalent nature of the bonding and serve to tune-up the parameters of a new force field based on the atom-bond approach which correctly describes the main features of the H-2-coronene interaction. The structure and binding energies of (para-H-2) N-coronene clusters have been investigated with an additive model for the above mentioned interactions and exploiting basinhopping and path integral Monte Carlo calculations for N = 1- 16 at T = 2 K. Differences with respect to the prototypical (rare gas)(N)-coronene aggregates have been discussed.