Search results for "Restricted open-shell Hartree–Fock"

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Linear scaling exchange gradients for Hartree–Fock and hybrid density functional theory

2000

Abstract A new method is introduced which allows to form the exchange part of self-consistent field energy gradients in a way which scales linearly with molecular size for molecules with a non-vanishing HOMO–LUMO gap. This is not only important for Hartree–Fock but as well for the popular hybrid density functional theory methods. The method preserves the optimized integral-driven structure of conventional direct methods. Efficiency and scaling behavior of the new method are illustrated for DNA fragments.

ChemistryMulti-configurational self-consistent fieldQuantum mechanicsHartree–Fock methodRestricted open-shell Hartree–FockGeneral Physics and AstronomyUnrestricted Hartree–FockDensity functional theoryStatistical physicsPhysical and Theoretical ChemistryScalingPost-Hartree–FockHybrid functionalChemical Physics Letters
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Analytic gradients for Mukherjee’s multireference coupled-cluster method using two-configurational self-consistent-field orbitals

2010

Analytic gradients for the state-specific multireference coupled-cluster method suggested by Mahapatra et al. [Mol. Phys. 94, 157 (1998)] (Mk-MRCC) are reported within the singles and doubles approximation using two-configurational self-consistent field (TCSCF) orbitals. The present implementation extends our previous work on Mk-MRCC gradients [E. Prochnow et al., J. Chem. Phys. 131, 064109 (2009)] which is based on restricted Hartree-Fock orbitals and consequently the main focus of the present paper is on the treatment of orbital relaxation at the TCSCF level using coupled-perturbed TCSCF theory. Geometry optimizations on m-arynes and nitrenes are presented to illustrate the influence of t…

Coupled clusterLinear combination of atomic orbitalsChemistryQuantum mechanicsRestricted open-shell Hartree–FockGeneral Physics and AstronomyMolecular orbital theoryMolecular orbitalComplete active spacePhysical and Theoretical ChemistrySlater-type orbitalBasis setThe Journal of Chemical Physics
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