TY - JOUR
T1 - High-order electron-correlation methods with scalar relativistic and spin-orbit corrections
AU - Hirata, So
AU - Yanai, Takeshi
AU - Harrison, Robert J.
AU - Kamiya, Muneaki
AU - Fan, Peng Dong
N1 - Funding Information:
The authors affiliated with University of Florida thank financial support from the U.S. Department of Energy (Grant No. DE-FG02-04ER15621). They are indebted to Dr. Zhiyong Zhang (Stanford University) and Professor Russell M. Pitzer (Ohio State University) for valuable technical advice.
PY - 2007
Y1 - 2007
N2 - An assortment of computer-generated, parallel-executable programs of ab initio electron-correlation methods has been fitted with the ability to use relativistic reference wave functions. This has been done on the basis of scalar relativistic and spin-orbit effective potentials and by allowing the computer-generated programs to handle complex-valued, spinless orbitals determined by these potentials. The electron-correlation methods that benefit from this extension are high-order coupled-cluster methods (up to quadruple excitation operators) for closed- and open-shell species, coupled-cluster methods for excited and ionized states (up to quadruples), second-order perturbation corrections to coupled-cluster methods (up to triples), high-order perturbation corrections to configuration-interaction singles, and active-space (multireference) coupled-cluster methods for the ground, excited, and ionized states (up to active-space quadruples). A subset of these methods is used jointly such that the dynamical correlation energies and scalar relativistic effects are computed by a lower-order electron-correlation method with more extensive basis sets and all-electron relativistic treatment, whereas the nondynamical correlation energies and spin-orbit effects are treated by a higher-order electron-correlation method with smaller basis sets and relativistic effective potentials. The authors demonstrate the utility and efficiency of this composite scheme in chemical simulation wherein the consideration of spin-orbit effects is essential: ionization energies of rare gases, spectroscopic constants of protonated rare gases, and photoelectron spectra of hydrogen halides.
AB - An assortment of computer-generated, parallel-executable programs of ab initio electron-correlation methods has been fitted with the ability to use relativistic reference wave functions. This has been done on the basis of scalar relativistic and spin-orbit effective potentials and by allowing the computer-generated programs to handle complex-valued, spinless orbitals determined by these potentials. The electron-correlation methods that benefit from this extension are high-order coupled-cluster methods (up to quadruple excitation operators) for closed- and open-shell species, coupled-cluster methods for excited and ionized states (up to quadruples), second-order perturbation corrections to coupled-cluster methods (up to triples), high-order perturbation corrections to configuration-interaction singles, and active-space (multireference) coupled-cluster methods for the ground, excited, and ionized states (up to active-space quadruples). A subset of these methods is used jointly such that the dynamical correlation energies and scalar relativistic effects are computed by a lower-order electron-correlation method with more extensive basis sets and all-electron relativistic treatment, whereas the nondynamical correlation energies and spin-orbit effects are treated by a higher-order electron-correlation method with smaller basis sets and relativistic effective potentials. The authors demonstrate the utility and efficiency of this composite scheme in chemical simulation wherein the consideration of spin-orbit effects is essential: ionization energies of rare gases, spectroscopic constants of protonated rare gases, and photoelectron spectra of hydrogen halides.
UR - http://www.scopus.com/inward/record.url?scp=33846400493&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846400493&partnerID=8YFLogxK
U2 - 10.1063/1.2423005
DO - 10.1063/1.2423005
M3 - Article
AN - SCOPUS:33846400493
SN - 0021-9606
VL - 126
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 2
M1 - 024104
ER -