Abstract
We present Unsöld-W12 (UW12), an approximation to the correlation energy of molecules that is an explicit functional of the single-particle reduced-density matrix. The approximation resembles one part of modern explicitly correlated second-order Møller-Plesset (MP2) theory and is intended as an alternative to MP2 in double-hybrid exchange-correlation functionals. Orbital optimization with UW12 is straightforward, and the UW12 energy is evaluated without a double summation over unoccupied orbitals, leading to a faster basis-set convergence than is seen in double-hybrid functionals. We suggest a one-parameter hybrid exchange-correlation functional XCH-BLYP-UW12. XCH-BLYP-UW12 is similar to double-hybrid functionals, but contains UW12 correlation instead of MP2 correlation. We find that XCH-BLYP-UW12 is more accurate than the existing double-hybrid functional B2-PLYP for small-molecule main-group reaction barrier heights and has roughly the same accuracy as the existing hybrid functional B3LYP for atomization energies.
Original language | English |
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Pages (from-to) | 4590-4599 |
Number of pages | 10 |
Journal | Journal of Chemical Theory and Computation |
Volume | 14 |
Issue number | 9 |
Early online date | 6 Aug 2018 |
DOIs | |
Publication status | Published - 11 Sep 2018 |
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Datasets
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Unsöld functional
Manby, F. R. (Creator) & Wiles, T. (Creator), University of Bristol, 21 Aug 2018
DOI: 10.5523/bris.fxmuvujgeid2css1z2krpe3o, http://data.bris.ac.uk/data/dataset/fxmuvujgeid2css1z2krpe3o
Dataset
Profiles
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Professor Frederick R Manby
- School of Chemistry - Professor of Theoretical Chemistry
- Computational and Theoretical Chemistry
Person: Academic , Member