The RAS-CCSD model, with applications for open-shell molecules
Sarai Dery Folkestad
Abstract
The restricted active space coupled cluster singles and doubles (RAS-CCSD) model, and its pilot implementation is detailed. The approach offers a simple, pragmatic way to formulate a coupled cluster theory for open-shell and multireference systems. For ground state energies, errors (compared to FCI) are shown to be similar to those of unrestricted (spin-orbital) CCSD. For excited states, the errors of RAS-CCSD are generally larger, and adaptations to the methodology are needed to achieve an approach which is balanced for both ground and excited states. However, unlike unrestricted CCSD, the approach is spin-adapted and can be used to add dynamical correlation to a multideterminantal reference state.
Create a lesson
Related papers
Kernel-Level Constant-Potential Molecular Dynamics in GROMACS
Sheng Bi, Mathieu Salanne, Jun Cheng et al.
Tersoff-NN: Hybrid Machine-Learned Bond-Order Extension of the Tersoff Potential
Yusuke Nishimura, Sho Kubota, Kotaro Takematsu et al.
Learning Electron Density with Virtual Atoms for Transferable Atomistic Representations
Yuzhi Liu, Xinzijian Liu, Chengqian Zhang et al.
UGME: A python package for non-Markovian protein folding dynamics
Anthony J. Dominic, Bertram Cham, Andrés Montoya-Castillo
Spin Migration in the Argon Dimer
Stefanos Carlström, Serguei Patchkovskii, Misha Yu Ivanov
Accuracy of Vibrational Properties of Machine-Learning Force Fields for Molecular Crystal Transformations
Natalia Goncharova, Oskar Schweighofer, Johannes Hoja