Using a Lagrangian-based approach, we present a more elegant derivation of the equations
necessary for the variational optimization of the molecular orbitals (MOs) for the coupled …

In this research, orbital-optimized third-order Møller-Plesset perturbation theory (OMP3) and
its spin-component and spin-opposite scaled variants (SCS-OMP3 and SOS-OMP3) are …

are presented. The OMP3 method is applied to problematic chemical systems with
challenging electronic structures. The performance of the OMP3 method is compared with …

Multicomponent quantum chemistry methods such as the nuclear-electronic orbital (NEO)
method allow the consistent quantum mechanical treatment of electrons and nuclei. The …

Orbital-optimized MP2. 5 [or simply “optimized MP2. 5,” OMP2. 5, for short] and its analytic
energy gradients are presented. The cost of the presented method is as much as that of …

An efficient formulation of the analytic energy gradient for the single and double excitation
coupled‐cluster method that includes a perturbational estimate of the effects of connected …

An efficient implementation of the orbital-optimized second-order Møller− Plesset
perturbation theory (OO-MP2) within the resolution of the identity (RI) approximation is …

Analytic energy gradients for the orbital-optimized second-order Møller–Plesset perturbation
theory (OMP2) are presented. The OMP2 method is applied to difficult chemical systems …

The extended Koopmans' theorem (EKT) provides a straightforward way to compute
ionization potentials (IPs) from any level of theory, in principle. However, for non-variational …

It is shown that due to the mixing of the usual projection approach of coupled cluster with
variational orbital optimization, orbital-optimized coupled cluster (OCC) fails to reproduce …