DMRG-based externally corrected multireference coupled cluster methods

Abstract: Since its invention in solids state physics, the density matrix renormalization group (DMRG) method has proven itself as a powerful method for description of strongly correlated systems. In the last decade, it has also been successfully applied in quantum chemistry, where it has become a method of choice for strongly multiconfigurational systems. Nevertheless, to achieve the ``chemical accuracy', its lack of description of the dynamic correlation is a serious drawback. We suggest to combine the DMRG method and externally corrected coupled cluster techniques, which will exploit the information obtained from DMRG and include the remaining dynamic correlation effects missing in DMRG itself. We expect the resulting methods to be suitable for accurate and efficient calculations of strongly correlated molecular systems. Key words: coupled cluster; multireference; density matrix; renormalization group; DMRG