TY - JOUR
T1 - Active-space coupled-cluster methods through connected quadruple excitations
AU - Fan, Peng Dong
AU - Hirata, So
N1 - Funding Information:
This work has been supported by the U.S. Department of Energy, Office of Basic Energy Sciences DE-FG02-04ER15621. Some calculations were performed by using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the U.S. Department of Energy’s Office of Biological and Environmental Research and located at the Pacific Northwest National Laboratory (PNNL), operated for the Department of Energy by Battelle. The authors thank Dr. Karol Kowalski (PNNL) and Dr. Muneaki Kamiya (University of Florida) for useful discussions and Professor Piotr Piecuch (Michigan State University) for introducing them to the subject methods.
PY - 2006
Y1 - 2006
N2 - Coupled-cluster methods that include just a subset of all connected triple, quadruple, or both excitation amplitudes, according to the ansatz of and Adamowicz co-workers [Int. Rev. Phys. Chem. 12, 339 (1993); J. Chem. Phys. 99, 1875 (1993); 100, 5792 (1994)] and Piecuch [J. Chem. Phys. 110, 6103 (1999)], have been implemented into parallel execution programs. They are applicable to closed- and open-shell species and they take advantage of real Abelian point-group symmetry. A symbol manipulation program has been invoked to automate the implementation. These methods have been applied to the singlet-triplet separations of five triatomic hydrides (C H2, N H2+, Si H2, P H2+, and As H2+) with consideration of scalar relativistic effects. They have been shown to be remarkably effective with errors arising from the use of a very small subset of higher-order excitations being no more than a few tenths of 1 kcalmol.
AB - Coupled-cluster methods that include just a subset of all connected triple, quadruple, or both excitation amplitudes, according to the ansatz of and Adamowicz co-workers [Int. Rev. Phys. Chem. 12, 339 (1993); J. Chem. Phys. 99, 1875 (1993); 100, 5792 (1994)] and Piecuch [J. Chem. Phys. 110, 6103 (1999)], have been implemented into parallel execution programs. They are applicable to closed- and open-shell species and they take advantage of real Abelian point-group symmetry. A symbol manipulation program has been invoked to automate the implementation. These methods have been applied to the singlet-triplet separations of five triatomic hydrides (C H2, N H2+, Si H2, P H2+, and As H2+) with consideration of scalar relativistic effects. They have been shown to be remarkably effective with errors arising from the use of a very small subset of higher-order excitations being no more than a few tenths of 1 kcalmol.
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U2 - 10.1063/1.2178797
DO - 10.1063/1.2178797
M3 - Article
AN - SCOPUS:34547648255
SN - 0021-9606
VL - 124
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 10
M1 - 104108
ER -