Effects of London dispersion correction in density functional theory on the structures of organic molecules in the gas phase
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- 11 July 2013
- journal article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 15 (38), 16031-16042
- https://doi.org/10.1039/c3cp52293h
Abstract
A benchmark set of 25 rotational constants measured in the gas phase for nine molecules (termed ROT25) was compiled from available experimental data. The medium-sized molecules with 18–35 atoms cover common (bio)organic structure motifs including hydrogen bonding and flexible side chains. They were each considered in a single conformation. The experimental B0 values were back-corrected to reference equilibrium rotational constants (Be) by computation of the vibrational corrections ΔBvib. Various density functional theory (DFT) methods and Hartree–Fock with and without dispersion corrections as well as MP2 type methods and semi-empirical quantum chemical approaches are investigated. The ROT25 benchmark tests their ability to describe covalent bond lengths, longer inter-atomic distances, and the relative orientation of functional groups (intramolecular non-covalent interactions). In general, dispersion corrections to DFT and HF increase Be values (shrink molecular size) significantly by about 0.5–1.5% thereby in general improving agreement with the reference data. Regarding DFT methods, the overall accuracy of the optimized structures roughly follows the ‘Jacobs ladder’ classification scheme, i.e., it decreases in the series double-hybrid > (meta)hybrid > (meta)GGA > LDA. With B2PLYP-D3, SCS-MP2, B3LYP-D3/NL, or PW6B95-D3 methods and extended QZVP (def2-TZVP) AO basis sets, Be values, accurate to about 0.3–0.6 (0.5–1)% on average, can be computed routinely. The accuracy of B2PLYP-D3/QZVP with a mean deviation of only 3 MHz and a standard deviation of 0.24% is exceptional and we recommend this method when highly accurate structures are required or for problematic conformer assignments. The correlation effects for three inter-atomic distance regimes (covalent, medium-range, long) and the performance of minimal basis set (semi-empirical) methods are discussed.Keywords
This publication has 83 references indexed in Scilit:
- Rotational spectroscopy meets theoryPhysical Chemistry Chemical Physics, 2013
- Glycine conformers: a never-ending story?Physical Chemistry Chemical Physics, 2012
- Efficient and Accurate Double-Hybrid-Meta-GGA Density Functionals—Evaluation with the Extended GMTKN30 Database for General Main Group Thermochemistry, Kinetics, and Noncovalent InteractionsJournal of Chemical Theory and Computation, 2010
- The accuracy of rotational constants predicted by high-level quantum-chemical calculations. I. molecules containing first-row atomsThe Journal of Chemical Physics, 2008
- Density Functionals with Broad Applicability in ChemistryAccounts of Chemical Research, 2008
- Basis-set extrapolation techniques for the accurate calculation of molecular equilibrium geometries using coupled-cluster theoryThe Journal of Chemical Physics, 2006
- Density functional theory predictions of anharmonicity and spectroscopic constants for diatomic moleculesThe Journal of Chemical Physics, 2001
- Nobel Lecture: Electronic structure of matter—wave functions and density functionalsReviews of Modern Physics, 1999
- The prediction of molecular equilibrium structures by the standard electronic wave functionsThe Journal of Chemical Physics, 1997
- Zur Theorie und Systematik der MolekularkräfteThe European Physical Journal A, 1930