Embedding methods for Electronic Structure can provide accurate descriptions of chemical reactions

Welborn, M., Manby, F., Miller, T. Even-handed subsystem selection in projection-based embedding. The Journal of Chemical Physics, 149, 144101, DOI: https://doi.org/10.1063/1.5050533 (2018)


By treating different parts of a chemical system with different levels of theory, embedding methods for electronic structure can provide accurate description of chemical reactions at reduced computational cost.

In this paper, researchers looked at projection-based embedding that offers a simple framework for embedding correlated wavefunction methods in density functional theory. During a large geometry change—such as a chemical reaction—the nature of these localized molecular orbitals, as well as their partitioning into the two subsystems, can change dramatically. This work presents an even-handed framework for localized orbital partitioning that ensures consistent subsystems across a set of molecular geometries. SN2 reactions were used as illustrations of this approach. Applications to a nitrogen umbrella flip in a cobalt-based CO2 reduction catalyst and to the binding of CO to Cu clusters are presented in the paper.

Contact: tfm@caltech.edu

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Reprinted from Welborn, M., Manby, F., Miller, T. Even-handed subsystem selection in projection-based embedding. The Journal of Chemical Physics, 149, 144101, DOI:  https://doi.org/10.1063/1.5050533  (2018)   Embedding calculations on the formation of a hydrogen bond between a cobalt aminopyridine complex and a bound CO2 molecule. (a) Reactant, transition state, and product geometries illustrated with opaque subsystem A atoms and transparent subsystem B atoms. Two views are shown for each geometry. (b) B3LYP, PBE, and PBE-in-B3LYP energy profiles, with three methods of LMO selection for the last. (c) Energy profiles from MRCI embedded in B3LYP and in PBE using even-handed LMO selection. All curves are referenced to an energy of zero at the reactant geometry. The number of occupied LMOs in subsystem A is given in parentheses (out of 121 total).

Reprinted from Welborn, M., Manby, F., Miller, T. Even-handed subsystem selection in projection-based embedding. The Journal of Chemical Physics, 149, 144101, DOI: https://doi.org/10.1063/1.5050533 (2018)

Embedding calculations on the formation of a hydrogen bond between a cobalt aminopyridine complex and a bound CO2 molecule. (a) Reactant, transition state, and product geometries illustrated with opaque subsystem A atoms and transparent subsystem B atoms. Two views are shown for each geometry. (b) B3LYP, PBE, and PBE-in-B3LYP energy profiles, with three methods of LMO selection for the last. (c) Energy profiles from MRCI embedded in B3LYP and in PBE using even-handed LMO selection. All curves are referenced to an energy of zero at the reactant geometry. The number of occupied LMOs in subsystem A is given in parentheses (out of 121 total).