Center for Molecular Modeling - Y.X. Cheng

A new framework for frequency-dependent polarizable force fields

leen — Tue, 10 Jan 2023 13:26:45 +0000

Y.X. Cheng, T. Verstraelen

Journal of Chemical Physics

157, 12

2022

Abstract

A frequency-dependent extension of the polarizable force field “Atom-Condensed Kohn–Sham density functional theory approximated to the second-order” (ACKS2) [Verstraelen et al., J. Chem. Phys. 141, 194114 (2014)] is proposed, referred to as ACKS2ω. The method enables theoretical predictions of dynamical response properties of finite systems after partitioning of the frequency-dependent molecular response function. Parameters in this model are computed simply as expectation values of an electronic wavefunction, and the hardness matrix is entirely reused from ACKS2 as an adiabatic approximation is used. A numerical validation shows that accurate models can already be obtained with atomic monopoles and dipoles. Absorption spectra of 42 organic and inorganic molecular monomers are evaluated using ACKS2ω, and our results agree well with the time-dependent DFT calculations. Also for the calculation of C₆ dispersion coefficients, ACKS2ω closely reproduces its TDDFT reference. When parameters for ACKS2ω are derived from a PBE/aug-cc-pVDZ ground state, it reproduces experimental values for 903 organic and inorganic intermolecular pairs with an MAPE of 3.84%. Our results confirm that ACKS2ω offers a solid connection between the quantum-mechanical description of frequency-dependent response and computationally efficient force-field models. Published under an exclusive license by AIP Publishing.

DOI

http://dx.doi.org/10.1063/5.0115151

A new framework for frequency-dependent polarizable force fields

yingxing — Mon, 05 Sep 2022 12:07:02 +0000

Y.X. Cheng, T. Verstraelen

Journal of Chemical Physics

2022

Abstract

A frequency-dependent extension of the polarizable force field "Atom-Condensed Kohn-Sham density functional theory approximated to the second-order'' (ACKS2) [J. Chem. Phys. 141, 194114 (2014)] is proposed, referred to as ACKS2$\omega$. The method enables theoretical predictions of dynamical response properties of finite systems after a partitioning of the frequency-dependent molecular response function. Parameters in this model are computed simply as expectation values of an electronic wavefunction, and the hardness matrix is entirely reused from ACKS2 as an adiabatic approximation is used. A numerical validation shows that accurate models can already be obtained with atomic monopoles and dipoles. Absorption spectra of 42 organic and inorganic molecular monomers are evaluated using ACKS2$\omega$, and our results agree well with the time-dependent DFT calculations. Also for the calculation of $C_6$ dispersion coefficients, ACKS2$\omega$ closely reproduces its TDDFT reference. When parameters for ACKS2$\omega$ are derived from a PBE/aug-cc-pVDZ ground state, it reproduces experimental values for 903 organic and inorganic intermolecular pairs with an MAPE of 3.84%. Our results confirm that ACKS2$\omega$ offers a solid connection between the quantum-mechanical description of frequency-dependent response and computationally efficient force-field models.

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