Accurate predictions of the electronic excited states of BODIPY based dye sensitizers using spin-component-scaled double-hybrid functionals: a TD-DFT benchmark study

The excitation energies of 13 BODIPY dye sensitizers are benchmarked by means of TD-DFT, using 36 functionals. Spin-component-scaled double-hybrid (DSD) functionals are found to show the best performance.

Defect Calculation by Combined SCAN and Hybrid Functional in γ-CsPbI3

γ-CsPbI3 solar cells have achieved promising efficiencies, yet the quantitative understanding of their defect properties is limited due to severe computational challenges of hybrid functionals. We have discovered an algorithm...

Dispersion Corrected r2SCAN Based Global Hybrid Functionals: r2SCANh, r2SCAN0, and r2SCAN50

The re-regularized semilocal meta generalized gradient approximation (meta-GGA) exchange-correlation functional r2SCAN [J. W. Furness, A. D. Kaplan, J. Ning, J. P. Perdew, and J. Sun, J. Phys. Chem. Lett. 11, 8208–8215 (2020)] is used to create the three global hybrid functionals with varying admixtures of Hartree–Fock exact exchange (HFX). The resulting exchange-correlation functionals r2SCANh (10% HFX), r2SCAN0 (25% HFX), and r2SCAN50 (50%HFX) are combined with the recent semi-classical D4 London dispersion correction. The new functionals are assessed for molecular geometries, general main-group, and metalorganic thermochemistry at 26 comprehensive benchmark sets including such as the large GMTKN55, ROST61, and IONPI19 sets. It is shown that a moderate admixture of HFX leads to overall mean percentual improvements of −11 (r2SCANh-D4), −16 (r2SCAN0-D4), and −1% (r2SCAN50-D4) regarding thermochemistry compared to the parental meta-GGA. For organometallic reaction energies and barriers, r2SCAN0-D4 even yields a mean improvement of −35%. The computation of structural parameters does not systematically profit from HFX admixture. Overall, the most promising combination r2SCAN0-D4 performs well for both main-group and organometallic thermochemistry. It yields deviations better or on par with other very well-performing global hybrid functionals such as PW6B95-D4 or PBE0-D4. Regarding systems prone to self-interaction errors (SIE4x4), r2SCAN0-D4 shows reasonable performance, reaching the quality of the range-separated ωB97X-V functional. Accordingly, r2SCAN0-D4 in combination with a sufficiently converged basis set (def2-QZVP(P)) represents a robust and reliable choice for general use in the calculation of thermochemical properties of both, main-group and organometallic chemistry.

High-Throughput Predictions of Metal–Organic Framework Electronic Properties: Theoretical Challenges, Graph Neural Networks, and Data Exploration

With the goal of accelerating the design and discovery of metal–organic frameworks (MOFs) for (opto)electronic and energy storage applications, we present a new dataset of predicted electronic structure properties for thousands of MOFs carried out using multiple density functional approximations. Compared to more accurate hybrid functionals, we find that the widely used PBE generalized gradient approximation (GGA) functional severely underpredicts MOF band gaps in a largely systematic manner for semi-conductors and insulators without magnetic character. However, an even larger and less predictable disparity in the band gap prediction is present for MOFs with open-shell 3d transition metal cations. With regards to partial atomic charges, we find that different density functional approximations predict similar charges overall, although hybrid functionals tend to shift electron density away from the metal centers and onto the ligand environments compared to the GGA point of reference. Much more significant differences in partial atomic charges are observed when comparing different charge partitioning schemes. We conclude by using the new dataset of computed MOF properties to train machine learning models that can rapidly predict MOF band gaps for all four density functional approximations considered in this work, paving the way for future high-throughput screening studies. To encourage exploration and reuse of the theoretical calculations presented in this work, the curated data is made publicly available via an interactive and user-friendly web application on the Materials Project.

A Computational Journey across Nitroxide Radicals: From Structure to Spectroscopic Properties and Beyond

Nitroxide radicals are characterized by a long-lived open-shell electronic ground state and are strongly sensitive to the chemical environment, thus representing ideal spin probes and spin labels for paramagnetic biomolecules and materials. However, the interpretation of spectroscopic parameters in structural and dynamic terms requires the aid of accurate quantum chemical computations. In this paper we validate a computational model rooted into double-hybrid functionals and second order vibrational perturbation theory. Then, we provide reference quantum chemical results for the structures, vibrational frequencies and other spectroscopic features of a large panel of nitroxides of current biological and/or technological interest.