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Abstract
Dipole moments are the first moment of electron density and are fundamental quantities that are often available from experiments. An exchangecorrelation functional that leads to an accurate representation of the charge distribution of a molecule should accurately predict the dipole moments of the molecule. It is well known that KohnSham density functional theory (DFT) is more accurate for the energetics of singlereference systems than for the energetics of multireference ones, but there has been less study of charge distributions. In this work, we benchmark 48 density functionals chosen with various combinations of ingredients, against accurate experimental data for dipole moments of 78 molecules, in particular 55 singlereference molecules and 23 multireference ones. We chose both organic and inorganic molecules, and within the category of inorganic molecules there are both maingroup and transitionmetalcontaining molecules, with some of them being multireference. As one would expect, the multireference molecules are not as well described by singlereference DFT, and the functionals tested in this work do show larger mean unsigned errors (MUEs) for the 23 multireference molecules than the singlereference ones. Five of the 78 molecules have relatively large experimental error bars and were therefore not included in calculating the overall MUEs. For the 73 molecules not excluded, we find that three of the hybrid functionals, B971, PBE0, and TPSSh (each with less than or equal to 25% HartreeFock (HF) exchange), the rangeseparated hybrid functional, HSE06 (with HF exchange decreasing from 25% to 0 as interelectronic distance increases), and the hybrid functional, PW6B95 (with 28% HF exchange) are the best performing functionals with each yielding an MUE of 0.18 D. Perhaps the most significant finding of this study is that there exists great similarity among the success rate of various functionals in predicting dipole moments. In particular, of 39 functionals designed as generalpurpose functionals and that do not have a global value of 100% HF exchange, the average MUE is 0.23 D, with a standard deviation of only 0.04 D. Among gradient approximations, which are especially interesting because of their speed and portability, the best overall performance is by PBE, HCTH/407, OLYP, OreLYP, and GAM, each with MUE of 0.22 D.
Original language  English (US) 

Pages (fromto)  1289812912 
Number of pages  15 
Journal  Physical Chemistry Chemical Physics 
Volume  19 
Issue number  20 
DOIs  
State  Published  Jan 1 2017 
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Projects
 1 Finished

NMGC: Nanoporous Materials Genome: Methods and Software to Optimize Gas Storage, Separations, and Catalysis (Phase 1)
Siepmann, I., Cramer, C., Gagliardi, L., Truhlar, D. G., Tsapatsis, M. & Goodpaster, J. D.
9/1/12 → 8/31/17
Project: Research project