Polarizable Embedding Density Matrix Renormalization Group.

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Electronic Structure Theory

Background:

• The polarizable embedding (PE) approach models quantum mechanical subsystems interacting with their environment.
• Environmental polarization is crucial for accurate electronic structure calculations.
• Existing methods may struggle with systems requiring large active spaces due to static electron correlation.

Purpose of the Study:

• To introduce and validate the polarizable embedding-density matrix renormalization group (PE-DMRG) method.
• To enable accurate calculations of strongly correlated electronic structures in complex molecular environments.
• To investigate environmental effects on electronic excited states.

Main Methods:

• Coupling the polarizable embedding (PE) approach with the density matrix renormalization group (DMRG).
• Utilizing atom-centered multipoles and polarizabilities to model environmental interactions.
• Employing large active spaces suitable for multiconfigurational electronic structure problems.

Main Results:

• The PE-DMRG method successfully describes strongly correlated electronic structures.
• Investigated the first excited state of water using various embedding potentials.
• Analyzed environmental effects on the excited state of a retinylidene Schiff base in channelrhodopsin, including dynamical correlation via DFT.

Conclusions:

• PE-DMRG is a powerful tool for studying complex molecular systems with dense frontier orbital manifolds.
• The method accurately accounts for both static and dynamical electron correlation effects in embedded environments.
• This approach enhances the capability to model challenging electronic structure problems in realistic molecular settings.