Coupled Cluster Methods Tailored by Matrix Product State Wave Functions
Libor Veis1, Andrej Antalík1, Jan Brandejs1, Jakub Lang1, Jiří Brabec1, Frank Neese2, Örs Legeza3, Jiří Pittner1
1J. Heyrovský Institute of Physical Chemistry, ASCR, 18223 Prague, Czech Republic
2Max Planck Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470
Mülheim an der Ruhr, Germany
3Strongly Correlated Systems “Lendület” Research group, Wigner Research Centre for Physics, H-1525 Budapest, Hungary
In the past decade, the quantum chemical version of the density matrix renormalization group (DMRG) method [1, 2] has established itself as the method of choice for calculations of strongly correlated molecular systems. Despite its favorable scaling which allows treatment of large active spaces, it is in practice not suitable for computations of dynamic correlation. We review our recent efforts in development of accurate “post-DMRG” methods for treatment of dynamic correlation on top of the DMRG wave function (so called matrix product state wave function [3]), which are based on the tailored coupled cluster (CC) theory [4]. The DMRG method is indeed responsible for the proper description of non-dynamic correlation, whereas dynamic correlation is incorporated by CC [5].
At first, we introduce the standard DMRG-TCCSD method and illustrate its performance on a couple of strongly correlated molecular systems ranging from biradicals to transition metal complexes [5, 6].
Furthermore, we present the recent DMRG-TCCSD implementation based on the local pair natural orbital formalism (LPNO) with dramatically reduced scaling and its application to the electronic structure of oxo-Mn(Salen) [7].
Last but not least, we introduce the Hilbert space multireference generalization of the DMRGTCCSD method, which removes the biggest bottleneck of the original DMRG-TCCSD method, namely the single reference bias.
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[5] L. Veis, A. Antalík, J. Brabec, F. Neese, Ö. Legeza, J. Pittner, J. Phys. Chem. Lett. 7, 4072 (2016).
[6] L. Veis, A. Antalík, Ö. Legeza, A. Alavi, J. Pittner, J. Chem. Theory Comput. 14, 2439 (2018).
[7] A. Antalík, L. Veis, F. Neese, Ö. Legeza, J. Pittner, in preparation.