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Domenichini G. Extending the definition of atomic basis sets to atoms with fractional nuclear charge. J Chem Phys 2024; 160:124107. [PMID: 38526100 DOI: 10.1063/5.0196383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Accepted: 03/10/2024] [Indexed: 03/26/2024] Open
Abstract
Alchemical transformations showed that perturbation theory can be applied also to changes in the atomic nuclear charges of a molecule. The alchemical path that connects two different chemical species involves the conceptualization of a non-physical system in which an atom possess a non-integer nuclear charge. A correct quantum mechanical treatment of these systems is limited by the fact that finite size atomic basis sets do not define exponents and contraction coefficients for fractional charge atoms. This paper proposes a solution to this problem and shows that a smooth interpolation of the atomic orbital coefficients and exponents across the periodic table is a convenient way to produce accurate alchemical predictions, even using small size basis sets.
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Affiliation(s)
- Giorgio Domenichini
- Faculty of Physics, University of Vienna, Kolingasse 14-16, 1090 Vienna, Austria
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Sahre MJ, von Rudorff GF, Marquetand P, von Lilienfeld OA. Transferability of atomic energies from alchemical decomposition. J Chem Phys 2024; 160:054106. [PMID: 38341696 DOI: 10.1063/5.0187298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 01/09/2024] [Indexed: 02/13/2024] Open
Abstract
We study alchemical atomic energy partitioning as a method to estimate atomization energies from atomic contributions, which are defined in physically rigorous and general ways through the use of the uniform electron gas as a joint reference. We analyze quantitatively the relation between atomic energies and their local environment using a dataset of 1325 organic molecules. The atomic energies are transferable across various molecules, enabling the prediction of atomization energies with a mean absolute error of 23 kcal/mol, comparable to simple statistical estimates but potentially more robust given their grounding in the physics-based decomposition scheme. A comparative analysis with other decomposition methods highlights its sensitivity to electrostatic variations, underlining its potential as a representation of the environment as well as in studying processes like diffusion in solids characterized by significant electrostatic shifts.
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Affiliation(s)
- Michael J Sahre
- Vienna Doctoral School in Chemistry (DoSChem) and Institute of Theoretical Chemistry and Faculty of Physics, University of Vienna, 1090 Vienna, Austria
| | - Guido Falk von Rudorff
- Department of Chemistry, University Kassel, Heinrich-Plett-Str.40, 34132 Kassel, Germany
- Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Philipp Marquetand
- Faculty of Chemistry, Institute of Theoretical Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
| | - O Anatole von Lilienfeld
- Vienna Doctoral School in Chemistry (DoSChem) and Institute of Theoretical Chemistry and Faculty of Physics, University of Vienna, 1090 Vienna, Austria
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, St. George Campus, Toronto, M5S 3H6 Ontario, Canada
- Department of Materials Science and Engineering, University of Toronto, St. George Campus, Toronto, M5S 3E4 Ontario, Canada
- Vector Institute for Artificial Intelligence, Toronto, M5S 1M1 Ontario, Canada
- ML Group, Technische Universität Berlin and Institute for the Foundations of Learning and Data, 10587 Berlin, Germany
- Berlin Institute for the Foundations of Learning and Data, 10587 Berlin, Germany
- Department of Physics, University of Toronto, St. George Campus, Toronto, M5S 1A7 Ontario, Canada
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