Post-Density Matrix Renormalization Group Methods for Describing Dynamic Electron Correlation with Large Active...

Area of Science:

• Computational chemistry
• Quantum mechanics
• Materials science

Background:

• The ab initio density matrix renormalization group (DMRG) is a powerful numerical method for electronic structure calculations.
• Accurately describing dynamic correlation in large active spaces remains a challenge for standard DMRG.

Purpose of the Study:

• To provide an overview of ab initio DMRG principles.
• To review recent advancements in post-DMRG methods for capturing dynamic correlation.
• To discuss the classification, merits, and drawbacks of these advanced methods.

Main Methods:

• Overview of ab initio Density Matrix Renormalization Group (DMRG) principles.
• Classification of post-DMRG methods based on the use of n-electron reduced density matrices.
• Discussion of combinations with multireference quantum chemistry and density functional theory.

Main Results:

• Post-DMRG methods are categorized into two main types based on n-electron reduced density matrices.
• The merits and disadvantages of each category of post-DMRG methods are discussed.
• Identification of unsolved challenges and future development directions for post-DMRG approaches.

Conclusions:

• Post-DMRG methods offer promising avenues for quantitative electronic structure descriptions.
• Further development is needed to address bottlenecks in describing complex strongly correlated systems.
• These methods are expected to advance the study of large molecules and materials with intricate electronic structures.