Analytical nuclear gradients of the explicitly correlated Møller-Plesset second-order energy

Sebastian Höfener (1) , Wim Klopper (1)

1 KIT - Karlsruhe Institute of Technology

The analytical computation of nuclear gradients has been derived and implemented for the explicitly correlated second-order Møller-Plesset method (MP2-F12). The implementation has been accomplished in the Turbomole program package for ansatz MP2-F12/2*A. A Slater- type geminal expanded in six Gaussian geminals (STG-6G), a complementary auxiliary basis set (CABS), and robust density fitting approximations are used. In addition, a second-order perturbation theory correction for single excitations into the complementary auxiliary basis set (CABS singles) is included to reduce the Hartree-Fock error. Smooth convergence towards the basis set limit is observed for a selection of molecules. For computations on dimers of weakly interacting molecules in small basis sets, explicitly correlated second-order Møller- Plesset theory outperforms conventional second-order Møller-Plesset theory because basis set superposition errors are largely avoided at the MP2-F12/2*A level.

Mots clés: Physical Sciences

Sebastian Höfener, Wim Klopper. Analytical nuclear gradients of the explicitly correlated Møller-Plesset second-order energy. Molecular Physics, 2010, 108 (13), pp.1783-1796. ⟨10.1080/00268976.2010.490795⟩. ⟨hal-00608027⟩