Density matrix renormalization group with dynamical correlation via adiabatic connection

TL;DR

This paper introduces a hybrid method combining DMRG for strong correlation with adiabatic connection for dynamical correlation, enabling more accurate electronic structure calculations of complex molecules.

Contribution

It presents a novel approach integrating DMRG with adiabatic connection to efficiently include dynamical correlation in strongly correlated systems.

Findings

Successful application to n-acenes, Fe(II)-porphyrin, and Fe3S4 cluster.

Demonstrates improved accuracy over traditional DMRG methods.

Encouraging results suggest broad applicability.

Abstract

The quantum chemical version of the density matrix renormalization group (DMRG) method has established itself as one of the methods of choice for calculations of strongly correlated molecular systems. Despite its great ability to capture strong electronic correlation in large active spaces, it is not suitable for computations of dynamical electron correlation. In this work, we present a new approach to the electronic structure problem of strongly correlated molecules, in which DMRG is responsible for a proper description of the strong correlation, whereas dynamical correlation is computed via the recently developed adiabatic connection (AC) technique, which requires only up to two-body active space reduced density matrices. We report encouraging results of this approach on typical candidates for DMRG computations, namely the $n$-acenes ($n = 2 \rightarrow 7$), Fe(II)-porphyrin, and Fe$_3$S$_4$ cluster.