Speaker: Gergely Barcza (SZFI)
Title: Modeling correlated electronic systems
Date: 20 December 2022, 10 a.m.
Place: Building 1, Meeting room and online: https://wigner-hu.zoom.us/j/85263089740?pwd=M2sveFV2S2l2c21FWGVmMXFhZlN…
Meeting ID: 852 6308 9740
Correlation effects induced by interaction can be critical in the understanding of electronic systems. In this seminar, I give an overview of my recent research activities related to correlated effective models and ab initio systems. Furthermore, I discuss the restricted active space (RAS) method, which is designed to provide a balanced description of static and dynamical correlation effects of ab initio electronic systems. In the presented computational model, the strongly correlated orbitals are treated accurately, while the excitations for the weakly correlated orbitals are restricted. The density matrix renormalization method is capable of implementing straightforwardly the approach, which enables us to describe 10-20 strongly correlated molecular orbitals embedded in the environment of 100+ molecular orbitals. In addition, I demonstrate that the RAS method also provides an extrapolation scheme to estimate the exact energy.