Andrew T. B. Gilbert

TL;DR: Specific developments discussed include fast methods for density functional theory calculations, linear scaling evaluation of energies, NMR chemical shifts and electric properties, fast auxiliary basis function methods for correlated energies and gradients, equation-of-motion coupled cluster methods for ground and excited states, geminal wavefunctions, embedding methods and techniques for exploring potential energy surfaces.

TL;DR: A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided in this paper, covering approximately the last seven years, including developments in density functional theory and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces.

TL;DR: This article contains brief descriptive discussions of the key physical features of all new algorithms and theoretical models, together with sample calculations that illustrate their performance.

TL;DR: A simple algorithm, which is called the maximum overlap method (MOM), for finding excited-state solutions to self-consistent field (SCF) equations that maximizes the overlap between the occupied orbitals on successive SCF iterations to prevent variational collapse to the ground state.

TL;DR: The accuracy of core excitation energies and core electron binding energies computed within a Delta self-consistent-field framework is assessed and it is illustrated by the calculation of the pre-edge features in x-ray absorption spectra of plastocyanin, which shows that accurate results can be achieved with DeltaSelf-cons consistent-field calculations when used in conjunction with uncontracted basis functions.