期刊
JOURNAL OF CHEMICAL PHYSICS
卷 140, 期 10, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.4867383
关键词
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资金
- National Science Foundation (NSF) [NSF-CHE-1265277]
- Ministry of Education, Culture, Sports, Science and Technology-Japan (MEXT) [21550027]
- NSF [NSF-CHE-1112097]
- Department of Energy (DOE) [DE-SC0006650]
- Direct For Computer & Info Scie & Enginr
- Office of Advanced Cyberinfrastructure (OAC) [1265278] Funding Source: National Science Foundation
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [1112097] Funding Source: National Science Foundation
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [1265277] Funding Source: National Science Foundation
- Grants-in-Aid for Scientific Research [21550027, 25288013] Funding Source: KAKEN
- U.S. Department of Energy (DOE) [DE-SC0006650] Funding Source: U.S. Department of Energy (DOE)
We combine explicit correlation via the canonical transcorrelation approach with the density matrix renormalization group and initiator full configuration interaction quantum Monte Carlo methods to compute a near-exact beryllium dimer curve, without the use of composite methods. In particular, our direct density matrix renormalization group calculations produce a well-depth of D-e = 931.2 cm(-1) which agrees very well with recent experimentally derived estimates D-e = 929.7 +/- 2 cm(-1) [J. M. Merritt, V. E. Bondybey, and M. C. Heaven, Science 324, 1548 (2009)] and D-e = 934.6 cm(-1) [K. Patkowski, V. Spirko, and K. Szalewicz, Science 326, 1382 (2009)], as well the best composite theoretical estimates, D-e = 938 +/- 15 cm(-1) [K. Patkowski, R. Podeszwa, and K. Szalewicz, J. Phys. Chem. A 111, 12822 (2007)] and D-e = 935.1 +/- 10 cm(-1) [J. Koput, Phys. Chem. Chem. Phys. 13, 20311 (2011)]. Our results suggest possible inaccuracies in the functional form of the potential used at shorter bond lengths to fit the experimental data [J. M. Merritt, V. E. Bondybey, and M. C. Heaven, Science 324, 1548 (2009)]. With the density matrix renormalization group we also compute near-exact vertical excitation energies at the equilibrium geometry. These provide non-trivial benchmarks for quantum chemical methods for excited states, and illustrate the surprisingly large error that remains for 1 (1)Sigma(-)(g) state with approximate multi-reference configuration interaction and equation-of-motion coupled cluster methods. Overall, we demonstrate that explicitly correlated density matrix renormalization group and initiator full configuration interaction quantum Monte Carlo methods allow us to fully converge to the basis set and correlation limit of the non-relativistic Schrodinger equation in small molecules. (C) 2014 AIP Publishing LLC.
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