The subsystem quantum chemistry program Sᴇʀᴇɴɪᴛʏ

Abstract

SERENITY [J Comput Chem. 2018;39:788–798] is an open-source quantum chemistry software that provides an extensive development platform focused on quantum-mechanical multilevel and embedding approaches. In this study, we give an overview over the developments done in Serenity since its original publication in 2018. This includes efficient electronic-structure methods for ground states such as multilevel domain-based local pair natural orbital coupled cluster and Møller–Plesset perturbation theory as well as the multistate frozen-density embedding quasi-diabatization method. For the description of excited states, SERENITY features various subsystem-based methods such as embedding variants of coupled time-dependent density-functional theory, approximate second-order coupled cluster theory and the second-order algebraic diagrammatic construction technique as well as GW/Bethe–Salpeter equation approaches. SERENITY's modular structure allows combining these methods with density-functional theory (DFT)-based embedding through various practical realizations and variants of subsystem DFT including frozen-density embedding, potential-reconstruction techniques and projection-based embedding.