Stochastic Real-Time Second-Order Green’s Function Theory for Neutral Excitations in Molecules and Nanostructures

Leopoldo Mejía*, Jia Yin*, David R. Reichman*, Roi Baer*, Chao Yang*, Eran Rabani*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present a real-time second-order Green’s function (GF) method for computing excited states in molecules and nanostructures, with a computational scaling of O(Ne3), where Ne is the number of electrons. The cubic scaling is achieved by adopting the stochastic resolution of the identity to decouple the 4-index electron repulsion integrals. To improve the time propagation and the spectral resolution, we adopt the dynamic mode decomposition technique and assess the accuracy and efficiency of the combined approach for a chain of hydrogen dimer molecules of different lengths. We find that the stochastic implementation accurately reproduces the deterministic results for the electronic dynamics and excitation energies. Furthermore, we provide a detailed analysis of the statistical errors, bias, and long-time extrapolation. Overall, the approach offers an efficient route to investigate excited states in extended systems with open or closed boundary conditions.

Original languageAmerican English
Pages (from-to)5563-5571
Number of pages9
JournalJournal of Chemical Theory and Computation
Volume19
Issue number16
DOIs
StatePublished - 22 Aug 2023

Bibliographical note

Publisher Copyright:
© 2023 American Chemical Society

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