A quantum chemical study of H2S2: intramolecular torsional mode and intermolecular interactions with rare gases

The structural and energetic properties of the H2S2 molecule have been studied using density functional theory, second-order Møller–Plesset method, and coupled cluster theory with several basis sets. In order to extend previous work on intra- and intermolecular dynamics of the chirality changing modes for H2O2 and its derivatives, our focus has been on the torsion around the S–S bond, along with an extensive characterization of the intermolecular potentials of H2S2 with the rare gases He, Ne, Ar, and Kr. Use is made of previously defined coordinates and expansion formulas for the potentials which allow for a faithful representation of geometrical and symmetry properties of these systems that involve the interaction of an atom with a floppy molecule. The potential energy surfaces obtained in this work are useful for classical and quantum mechanical simulations of molecular collisions responsible for chirality changing processes of possible interest in the modeling of prebiotic phenomena.