Software for the frontiers of quantum chemistry: An overview of developments in the Q-Chem 5 package

This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange-correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear-electronic orbital method, and several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism and support for calculations on graphics processing units are described. Q-Chem boasts a community of well over 100 active academic developers, and the continuing evolution of the software is supported by an open teamware model and an increasingly modular design.

Automated summary

This article summarizes the technical advances in the fifth major release of the Q-Chem quantum chemistry program package, which includes developments since 2015. Q-Chem 5 features a variety of new many-body methods, core-level spectroscopy modeling tools, vibronic spectrum calculation methods, high-performance capabilities, and support for multithreaded parallelism. The software is continuously evolving with the support of an open teamware model and increasingly modular design, backed by a community of over 100 active academic developers.