Hybrid Gaussian–discrete-variable representation for describing molecular double-ionization events

Yip, Frank L.; McCurdy, C. William; Rescigno, T. N.

doi:10.1103/physreva.101.063404

Cited by 2 publications

(1 citation statement)

References 42 publications

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“…51,52 These states are now resonances and a suitable discretization for both localized and continuum states are needed to describe them. From a theoretical perspective, the scattering community has developed a wide range of tools to treat these resonance states, such as exterior complex scaling (ECS) [53][54][55][56][57][58][59][60] , complex absorbing potentials (CAP) [61][62][63][64][65][66][67][68][69] , and different grids as schemes to discretize space [70][71][72][73][74][75][76] . On the other hand, the quantum chemistry community has long advocated for the use of atomic orbital (AO) expansions based on Gaussian functions as an efficient way to compute ground and excited state properties of molecular systems.…”

Section: Static Field Ionization In a Finite Basismentioning

confidence: 99%

Exploring Spin Symmetry-Breaking Effects for Static Field Ionization of Atoms: Is There an Analog to the Coulson-Fischer Point in Bond Dissociation?

Cunha,

Lee,

Hait

et al. 2021

Preprint

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Section: Static Field Ionization In a Finite Basismentioning

confidence: 99%

Exploring Spin Symmetry-Breaking Effects for Static Field Ionization of Atoms: Is There an Analog to the Coulson-Fischer Point in Bond Dissociation?

Cunha,

Lee,

Hait

et al. 2021

Preprint

View full text Add to dashboard Cite

Exploring spin symmetry-breaking effects for static field ionization of atoms: Is there an analog to the Coulson–Fischer point in bond dissociation?

Cunha

Hait

McCurdy

et al. 2021

The Journal of Chemical Physics

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Löwdin’s symmetry dilemma is an ubiquitous issue in approximate quantum chemistry. In the context of Hartree–Fock (HF) theory, the use of Slater determinants with some imposed constraints to preserve symmetries of the exact problem may lead to physically unreasonable potential energy surfaces. On the other hand, lifting these constraints leads to the so-called broken symmetry solutions that usually provide better energetics, at the cost of losing information about good quantum numbers that describe the state of the system. This behavior has previously been extensively studied in the context of bond dissociation. This paper studies the behavior of different classes of HF spin polarized solutions (restricted, unrestricted, and generalized) in the context of ionization by strong static electric fields. We find that, for simple two electron systems, unrestricted Hartree–Fock (UHF) is able to provide a qualitatively good description of states involved during the ionization process (neutral, singly ionized, and doubly ionized states), whereas RHF fails to describe the singly ionized state. For more complex systems, even though UHF is able to capture some of the expected characteristics of the ionized states, it is constrained to a single Ms (diabatic) manifold in the energy surface as a function of field intensity. In this case, a better qualitative picture can be painted by using generalized Hartree–Fock as it is able to explore different spin manifolds and follow the lowest solution due to lack of collinearity constraints on the spin quantization axis.

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Hybrid Gaussian–discrete-variable representation for describing molecular double-ionization events

Cited by 2 publications

References 42 publications

Exploring Spin Symmetry-Breaking Effects for Static Field Ionization of Atoms: Is There an Analog to the Coulson-Fischer Point in Bond Dissociation?

Exploring Spin Symmetry-Breaking Effects for Static Field Ionization of Atoms: Is There an Analog to the Coulson-Fischer Point in Bond Dissociation?

Exploring spin symmetry-breaking effects for static field ionization of atoms: Is there an analog to the Coulson–Fischer point in bond dissociation?

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