title: Gaussian Basis Set and Planewave Relativistic Spin-Orbit Methods in NWChem.
abstract: Relativistic spin-orbit density functional theory (DFT) methods have been implemented in the molecular Gaussian DFT and pseudopotential planewave DFT modules of the NWChem electronic-structure program. The Gaussian basis set implementation is based upon the zeroth-order regular approximation (ZORA) while the planewave implementation uses spin-orbit pseudopotentials that are directly generated from the atomic Dirac-Kohn-Sham wave functions or atomic ZORA-Kohn-Sham wave functions. Compared to solving the full Dirac equation these methods are computationally efficient but robust enough for a realistic description of relativistic effects such as spin-orbit splitting, molecular orbital hybridization, and core effects. Both methods have been applied to a variety of small molecules, including I2, IF, HI, Br2, Bi2, AuH, and Au2, using various exchange-correlation functionals. Our results are in good agreement with experiment and previously reported calculations.
authors.affiliation: William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Mail Stop K8-91, Richland, Washington, 99352.
authors.forename: Patrick
authors.initials: P
authors.lastname: Nichols
authors.affiliation: William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Mail Stop K8-91, Richland, Washington, 99352.
authors.forename: Niranjan
authors.initials: N
authors.lastname: Govind
authors.affiliation: William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Mail Stop K8-91, Richland, Washington, 99352.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Bylaska
authors.affiliation: William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Mail Stop K8-91, Richland, Washington, 99352.
authors.forename: W A
authors.initials: WA
authors.lastname: de Jong