Spinfree formulation of reduced density matrices, density cumulants and generalised normal ordering

Kutzelnigg, Werner; Shamasundar, K. R.; Mukherjee, Debashis

doi:10.1080/00268970903547926

Cited by 51 publications

(58 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, we eliminated the four‐rank RDM using its cumulant reconstruction, which introduces the so‐called cumulant approximation errors. The cumulant reduction for 4‐RDM has been used by several earlier studies in the MR methods and also has been investigated by our group for the development of the cumulant‐approximated DMRG‐CASPT2 method . As a consequence, tensor contractions involving the 5‐RDM, whose size grows at the rate of o , are no longer necessary; thus, the σ ‐vector can be represented using the 1–3 rank RDMs.…”

Section: Methodsmentioning

confidence: 99%

Density matrix renormalization group for ab initio Calculations and associated dynamic correlation methods: A review of theory and applications

Yanai

Kurashige

Mizukami

et al. 2014

Int J of Quantum Chemistry

173

185

View full text Add to dashboard Cite

The recent advent of the density matrix renormalization group (DMRG) theory has delivered a new capability to compute multireference (MR) wave function with large configuration space, which far exceeds the limitation of conventional approaches. Here, we provide an overview of our recent work on the developments of ab initio DMRG methods in the context of the active space approaches and their applications to MR chemical systems.

show abstract

Section: Methodsmentioning

confidence: 99%

Density matrix renormalization group for ab initio Calculations and associated dynamic correlation methods: A review of theory and applications

Yanai

Kurashige

Mizukami

et al. 2014

Int J of Quantum Chemistry

173

185

View full text Add to dashboard Cite

show abstract

“…Note that the remaining low-order RDMs are computed from the DMRG wavefunction, for which we can use any type of molecular orbitals, such as LMOs, PCMOs, etc. As an additional variant, a cumulant approximation to 3-RDM based on the reconstruction form [78][79][80][81][82][83][84][85][86][87][88][89][90][91] …”

Section: B Cumulant Approximation To Rdmsmentioning

confidence: 99%

Complete active space second-order perturbation theory with cumulant approximation for extended active-space wavefunction from density matrix renormalization group

Kurashige

Chalupský

Lan

et al. 2014

The Journal of Chemical Physics

125

164

View full text Add to dashboard Cite

We report an extension of our previous development that incorporated quantum-chemical density matrix renormalization group (DMRG) into the complete active space second-order perturbation theory (CASPT2) [Y. Kurashige and T. Yanai, J. Chem. Phys. 135, 094104 (2011)]. In the previous study, the combined theory, referred to as DMRG-CASPT2, was built upon the use of pseudo-canonical molecular orbitals (PCMOs) for one-electron basis. Within the PCMO basis, the construction of the four-particle reduced density matrix (4-RDM) using DMRG can be greatly facilitated because of simplicity in the multiplication of 4-RDM and diagonal Fock matrix in the CASPT2 equation. In this work, we develop an approach to use more suited orbital basis in DMRG-CASPT2 calculations, e.g., localized molecular orbitals, in order to extend the domain of applicability. Because the multiplication of 4-RDM and generalized Fock matrix is no longer simple in general orbitals, an approximation is made to it using the cumulant reconstruction neglecting higher-particle cumulants. Also, we present the details of the algorithm to compute 3-RDM of the DMRG wavefunction as an extension of the 2-RDM algorithm of Zgid et al. [J. Chem. Phys. 128, 144115 (2008)] and Chan et al. [J. Chem. Phys. 128, 144117 (2008)]. The performance of the extended DMRG-CASPT2 approach was examined for large-scale multireference systems, such as low-lying excited states of long-chain polyenes and isomerization potential of {[Cu(NH3)3]2O2}(2+).

show abstract

“…The expression of vertex W ab ij is given as and Using the partial trace relation [39,40] it is easy to see that Ω a i (r) integrates to zero for all i, a:…”

Section: Asymptotic Behaviour Of Gvb-rccdmentioning

confidence: 99%

Calculation of dispersion interactions with the geminal-based ring Coupled Cluster Doubles method

Margócsy

Szabados

2020

Theor Chem Acc

View full text Add to dashboard Cite

show abstract

Spinfree formulation of reduced density matrices, density cumulants and generalised normal ordering

Cited by 51 publications

References 28 publications

Density matrix renormalization group for ab initio Calculations and associated dynamic correlation methods: A review of theory and applications

Density matrix renormalization group for ab initio Calculations and associated dynamic correlation methods: A review of theory and applications

Complete active space second-order perturbation theory with cumulant approximation for extended active-space wavefunction from density matrix renormalization group

Calculation of dispersion interactions with the geminal-based ring Coupled Cluster Doubles method

Contact Info

Product

Resources

About