Ab initio density matrix renormalization group

In modest sized systems, we can treat the nondynamic correlation in an active space. For systems with up to 14 orbitals, the complete-active-space self-consistent field (CASSCF) theory provides a very satisfactory description [2, 3]. More recently, the ab initio density matrix renormalization group (DMRG) theory has allowed us to obtain a balanced description of nondynamic correlation for up to 40 active orbitals and more [4-13]. CASSCF and DMRG potential energy... 

Kurashige, Y., Yanai, T. High-performance ab initio density matrix renormalization group method applicability to large-scale multireference problems for metal compounds. J. Chem. Phys. 2009, 130(23), 234114. 

S. R. White and R. L. Martin, Ab initio quantum chemistry using the density matrix renormalization group. J. Chem. Phys. 110, 4127 (1998). 

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