Evaluation of density functional theory for a large and diverse set of organic and inorganic equilibrium structures

Abstract

Density functional theory (DFT) has been extensively benchmarked for energetic properties; however, less attention has been given to equilibrium structures and the effect of using a certain DFT geometry on subsequent energetic properties. We evaluate the performance of 52 contemporary DFT methods for obtaining the structures of 122 species in the W4-11-GEOM database. This dataset includes a total of 246 unique bonds: 117 H─X, 65 X─Y, 49 X═Y, and 15 X Y bonds (where X and Y are first-and second-row atoms) and 133 key bond angles: 96 X-Y-H, 22 X-Y-Z, and 15 H-X-H angles. The reference geometries are optimized at the CCSD(T)/jul-cc-pV (n+d)Z level of theory (n = 5, 6). The performance of DFT is evaluated in conjunction with the Def2-nZVPP (n = T, Q), cc-pV(T+d)Z, and jul-cc-pV(T+d)Z basis sets. The root-mean-square deviations (RMSDs) over the bond distances of the best performing functionals from each rung of Jacob's Ladder are 0.0086 (SOGGA11), 0.0088 (τ-HCTH), 0.0059 (B3LYP), 0.0054 (TPSSh), and 0.0032 (DSD-PBEP86) Å.We evaluate the effect of the choice of the DFT geometry on subsequent molecular energies calculated with W1-F12 theory. Geometries obtained with GGA and MGGA methods result in large RMSDs in the subsequent W1-F12 energies; however, six hybrid GGA functionals (B3LYP, B3P86, mPW3PBE, B3PW91, mPW1LYP, and X3LYP) result in an excellent performance with RMSDs between 0.25 and 0.30 kJ mol À1 relative to the CCSD(T)/CBS reference geometries. The B2GP-PLYP and mPW2-PLYP DHDFT methods result in near-CCSD(T) accuracy with RMSDs of 0.11 and 0.10 kJ mol À1 , respectively.

Accurate Heats of Formation for Polycyclic Aromatic Hydrocarbons: A High-Level Ab Initio Perspective

“…The geometries of all structures have been obtained at the B3LYP-D3/A′VTZ level of theory. − We note that the D3 dispersion correction is expected to have a minor effect on the final geometries and a negligible effect on the final W1-F12 energies . For example, for C 6 H 6 and C 10 H 8 , the MADs between the B3LYP/A′VTZ and B3LYP-D3/A′VTZ bond distances are 0.00018 Å (over the five unique CC bonds) and 0.00005 Å (over the three unique C–H bonds).…”

Accurate Biomolecular Structures by the Nano-LEGO Approach: Pick the Bricks and Build Your Geometry

“…The knowledge of detailed molecular geometries in the gas phase is the mandatory prerequisite for the study of their physical–chemical properties and for the disentanglement of stereo-electronic, vibrational, and environmental effects that ultimately define the overall experimental observables. − Moreover, accurate geometries of isolated molecules provide the best benchmarks for the validation of different quantum mechanical (QM) approaches − and for the development of accurate force fields to be used in molecular mechanics (MM) or multi-level QM/MM models for the study of systems too large to be amenable to the most accurate QM studies. Unfortunately, the determination of accurate equilibrium geometries for molecules of increasing size is not straightforward at all from both experimental and theoretical viewpoints.…”

DFT, ADMET and Molecular Docking Investigations for the Antimicrobial Activity of 6,6′-Diamino-1,1′,3,3′-tetramethyl-5,5′-(4-chlorobenzylidene)bis[pyrimidine-2,4(1H,3H)-dione]

“…The chemical potential (µ) indicates the possibility of a chemical reaction, the high value of μ (less negative) means it is easier to donate electrons (electron donor), while a small value of μ (more negative) means it is easier to accept electrons (electron acceptor). Electronegativity (χ) of a molecule measures its ability for electron attraction [ 34 ]. The chemical potential is calculated to be (−3.29 eV), describing the molecule as donor electrons.…”