During the past decade, the research field of computational X-ray spectroscopy has
witnessed an advancement triggered by the development of advanced synchrotron light …

Psi4 is an ab initio electronic structure program providing methods such as Hartree–Fock,
density functional theory, configuration interaction, and coupled-cluster theory. The 1.1 …

We introduce a unitary coupled-cluster (UCC) ansatz termed k-UpCCGSD that is based on a
family of sparse generalized doubles operators, which provides an affordable and …

Recent progress in the field of (time-independent) ensemble density-functional theory (DFT)
for excited states are reviewed. Both Gross–Oliveira–Kohn (GOK) and N-centered ensemble …

We present a general approach to converge excited state solutions to any quantum
chemistry orbital optimization process, without the risk of variational collapse. The resulting …

We present a fully analytical implementation of the core–valence separation (CVS) scheme
for the equation-of-motion (EOM) coupled-cluster singles and doubles (CCSD) method for …

Orbital optimization is crucial when using a non-Aufbau Slater determinant that involves
promotion of an electron from a (nominally) occupied molecular orbital to an unoccupied …

The development of high-brilliance third-and fourth-generation light sources such as
synchrotrons and X-ray free-electron lasers (XFELs), the emergence of laboratory-based X …

Core-level spectra of 1s electrons of elements heavier than Ne show significant relativistic
effects. We combine advances in orbital-optimized density functional theory (OO-DFT) with …

Density functional theory (DFT) based modeling of electronic excited states is of importance
for investigation of the photophysical/photochemical properties and spectroscopic …