In this work, we apply the atomic resolution of the identity (ARI) fitting approximation to the computation of Hartree-Fock exchange. The ARI approximation is a local modification of the RI approximation that produces an energy which is differentiable with respect to nuclear motion, unlike other local applications of RI. We justify empirically the use of locality and present timing comparisons of ARI, RI, and exact computation for one-, two-, and three-dimensional carbon systems. ARI is found to reduce significantly the cost of RI for large systems, while retaining accuracy.
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http://dx.doi.org/10.1063/1.2828533 | DOI Listing |
J Chem Phys
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China.
Vibro-polaritons are hybrid light-matter states that arise from the strong coupling between the molecular vibrational transitions and the photons in an optical cavity. Developing theoretical and computational methods to describe and predict the unique properties of vibro-polaritons is of great significance for guiding the design of new materials and experiments. Here, we present the ab initio cavity Born-Oppenheimer density functional theory (CBO-DFT) and formulate the analytic energy gradient and Hessian as well as the nuclear and photonic derivatives of dipole and polarizability within the framework of CBO-DFT to efficiently calculate the harmonic vibrational frequencies, infrared absorption, and Raman scattering spectra of vibro-polaritons as well as to explore the critical points on the cavity potential energy surface.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
HUN-REN Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary.
Nat Commun
January 2025
Shanghai Key Laboratory of Molecular Catalysis and Innovation Materials, Collaborative Innovation Centre of Chemistry for Energy Materials, MOE Laboratory for Computational Physical Science, Department of Chemistry, Fudan University, Shanghai, China.
Hybrid density functionals, such as B3LYP and PBE0, have achieved remarkable success by substantially improving over their parent methods, namely Hartree-Fock and the generalized gradient approximation, and generally outperforming the second-order Møller-Plesset perturbation theory (MP2) that is more expensive. Here, we extend the linear scheme of hybrid multiconfiguration pair-density functional theory (HMC-PDFT) by incorporating a cross-entropy ingredient to balance the description of static and dynamic correlation effects, leading to a consistent improvement on both exchange and correlation energies. The B3LYP-like translated on-top functional (tB4LYP) developed along this line not only surpasses the accuracy of its parent methods, the complete active space self-consistent field (CASSCF) and the original MC-PDFT functionals (tBLYP and tB3LYP), but also outperforms the widely used complete active space second-order perturbation theory (CASPT2).
View Article and Find Full Text PDFJ Chem Theory Comput
December 2024
Department of Chemistry, Durham University, South Road, Durham DH1 3LE, U.K.
Classical reaction barriers in density-functional theory are considered from the perspective of the density-fixed adiabatic connection. A 'reaction adiabatic-connection integrand', , is introduced, where λ is the electron-electron interaction strength, for which equals the barrier, meaning the barrier can be easily visualized as the area under a plot of vs λ. For five chemical reactions, plots of reference , calculated from Lieb maximizations at the coupled-cluster level of theory, are compared with approximate , calculated from common exchange-correlation functionals using coordinate scaling, for coupled-cluster densities.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Manipal Centre for Natural Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India.
The magnetic nature of nonalternant hydrocarbon (Azulene) bridged nitronyl nitroxide (AzNN) and imino-nitroxide (AzIN) diradicals are investigated with 38 different DFT functionals to find out a correct functional to predict the magnetic nature of these diradicals. The effect of Hartree-Fock exchange (HFX) in the hybrid functionals are investigated for the prediction of magnetic nature of the nonalternant hydrocarbon bridged diradicals. The utility of Borden and Davidson's proposal of disjoint and nondisjoint SOMOs for the prediction of magnetic nature of alternant hydrocarbon bridged diradicals is assessed for the nonalternant hydrocarbon based diradicals.
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