Abstract

Simulation of molecular condensed phase systems require an accurate description of the interaction energy landscape. Rather large effects in local structure and phase behavior can be triggered by subtle changes or slight inaccuracies in the interaction potentials. An accurate simulation of the interaction forces requires a balanced calculation of strong and weak, short-range and long-range components. Wavefunction based correlation methods can help to achieve the necessary accuracy to make progress in the description of molecular condensed phase systems. We have recently succeeded in making such methods (MP2, dRPA, double-hybrid DFT ) available and have applied them to molecular solids and liquids. These applications showed the potential of the wavefunction methods, but also pointed to severe problems that have to be addressed. These problems, addressed by our most recent developments, include basis set dependence, system size and sampling convergence.