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RESEARCH PRODUCT
Cost-Effective Treatment of Scalar Relativistic Effects for Multireference Systems: A CASSCF Implementation Based on the Spin-free Dirac-Coulomb Hamiltonian
Filippo LippariniJürgen Gausssubject
Physics010304 chemical physicsScalar (mathematics)Computer Science Applications1707 Computer Vision and Pattern Recognition; Physical and Theoretical ChemistryComputer Science Applications1707 Computer Vision and Pattern Recognition010402 general chemistry01 natural sciencesFull configuration interaction0104 chemical sciencesComputer Science Applicationssymbols.namesakeQuantum mechanics0103 physical sciencesCoulombsymbolsEffective treatmentSpin symmetryPhysical and Theoretical ChemistryHamiltonian (quantum mechanics)Relativistic quantum chemistrydescription
We present an implementation of the complete active space-self-consistent field (CASSCF) method specifically designed to be used in four-component scalar relativistic calculations based on the spin-free Dirac-Coulomb (SFDC) Hamiltonian. Our implementation takes full advantage of the properties of the SFDC Hamiltonian that allow us to use real algebra and to exploit point-group and spin symmetry to their full extent while including in a rigorous way scalar relativistic effects in the treatment. The SFDC-CASSCF treatment is more expensive than its non-relativistic counterpart only in the orbital optimization step, while exhibiting the same computational cost for the rate-determining full configuration interaction part. The numerical aspects are discussed, and the capabilities of the SFDC-CASSCF methodology are demonstrated through a pilot application.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-07-28 |