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Journal article
The Grassmann interpolation method for spin-unrestricted open-shell systems
The Journal of chemical physics, Vol.158(21), 214104
06/07/2023
PMID: 37259994
Web of Science ID: WOS:001033564200017
Abstract
The recently reported Grassmann interpolation (G-Int) method [J. A. Tan and K. U. Lao, J. Chem. Phys. 158, 051101 (2023)] has been extended to spin-unrestricted open-shell systems. In contrast to closed-shell systems, where G-Int has to be performed only once since the alpha and beta density matrices are the same, spin-unrestricted open-shell systems require G-Int to be performed twice-one for the alpha spin and another for the beta spin density matrix. In this work, we tested the performance of G-Int to the carbon monoxide radical cation CO center dot+ and nickelocene complex, which have the doublet and triple ground states, respectively. We found that the Frobenius norm errors associated with the interpolations for the a and beta spin density matrices are comparable for a given molecular geometry. These G-Int density matrices, when used as an initial guess for a self-consistent field (SCF) calculation, outperform the conventional SCF guess schemes, such as the superposition of atomic densities, purified superposition of atomic densities, core Hamiltonian, and generalized Wolfsberg-Helmholtz approximation. Depending on the desired accuracy, these G-Int density matrices can be used to directly evaluate the SCF energy without performing SCF iterations. In addition, the spin-unrestricted G-Int density matrices have been used for the first time to directly calculate the atomic charges using the Mulliken and ChElPG population analysis.
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Details
- Title
- The Grassmann interpolation method for spin-unrestricted open-shell systems
- Publication Details
- The Journal of chemical physics, Vol.158(21), 214104
- Resource Type
- Journal article
- Publisher
- AIP Publishing
- Number of pages
- 8
- Grant note
- Virginia Commonwealth University College of Humanities and SciencesNational Energy Research Scientific Computing CenterOffice of Science of the U.S. Department of Energy: DE-AC02-05CH11231 NERSC: BES-ERCAP0020838
This work was supported by start-up funds from the Virginia Commonwealth University College of Humanities and Sciences. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using NERSC Award No. BES-ERCAP0020838. High performance computing resources provided by the High Performance Research Computing (HPRC) Core Facility at Virginia Commonwealth University (https://chipc.vcu.edu) were also used for conducting the research reported in this work.
- Copyright
- Rights managed by AIP Publishing.
- Identifiers
- WOS:001033564200017; 99381548017506600
- Academic Unit
- Chemistry; Hal Marcus College of Science and Engineering
- Language
- English