Double-linked Hylleraas configuration-interaction calculation for the nonrelativistic ground-state energy of the Be atom

Büsse, G.; Kleindienst, Heinz

doi:10.1103/physreva.51.5019

Cited by 11 publications

(2 citation statements)

References 10 publications

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“…Finiteelement MCHF and GTO basis set expansions coupled with MRSDCI were used to estimate the beryllium electron affinity by Olsen et al [61]. Although difficulties appear in computing matrix elements in the Hylleraas basis [62,63], Hylleraas configurationinteraction calculations were performed on the nonrelativistic ground-state energy of the Be atom [64]. The most accurate energies for the ground state of the beryllium-like atoms have been obtained using the exponentially correlated Gaussian basis sets [65,66].…”

Section: Exploring Computational Strategiesmentioning

confidence: 99%

Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations

Verdebout

Jönsson

Gaigalas

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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Multiconfiguration expansions frequently target valence correlation and correlation between valence electrons and the outermost core electrons. Correlation within the core is often neglected. A large orbital basis is needed to saturate both the valence and core-valence correlation effects. This in turn leads to huge numbers of configuration state functions (CSFs), many of which are unimportant. To avoid the problems inherent to the use of a single common orthonormal orbital basis for all correlation effects in the multiconfiguration Hartree-Fock (MCHF) method, we propose to optimize independent MCHF pair-correlation functions (PCFs), bringing their own orthonormal one-electron basis. Each PCF is generated by allowing single-and double-excitations from a multireference (MR) function. This computational scheme has the advantage of using targeted and optimally localized orbital sets for each PCF. These pair-correlation functions are coupled together and with each component of the MR space through a low dimension generalized eigenvalue problem. Nonorthogonal orbital sets being involved, the interaction and overlap matrices are built using biorthonormal transformation of the coupled basis sets followed by a counter-transformation of the PCF expansions. Applied to the ground state of beryllium, the new method gives total energies that are lower than the ones from traditional complete active space (CAS)-MCHF calculations using large orbital active sets. It is fair to say that we now have the possibility to account for, in a balanced way, correlation deep down in the atomic core in variational calculations.

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Section: Exploring Computational Strategiesmentioning

confidence: 99%

Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations

Verdebout

Jönsson

Gaigalas

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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show abstract

“…Also, the calculation, at least for He, is easier. This, in conjunction with modern computing power, might explain the renewed interest in Hy-CI techniques [ 25 , 26 , 27 , 28 , 29 , 20 ]. It was the impetus for our attempt to come up with a good technique for obtaining very accurate energies for few electron atomic systems using the Hy-CI formalism.…”

Section: High Precision Energies For Few-electron Atomic Systemsmentioning

confidence: 99%

Accelerating scientific discovery through computation and visualization II

Sims¹,

George²,

Satterfield³

et al. 2002

J. Res. Natl. Inst. Stand. Technol.

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This is the second in a series of articles describing a wide variety of projects at NIST that synergistically combine physical science and information science. It describes, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing, visualization, and machine learning to accelerate research. The examples include scientific collaborations in the following areas: (1) High Precision Energies for few electron atomic systems, (2) Flows of suspensions, (3) X-ray absorption, (4) Molecular dynamics of fluids, (5) Nanostructures, (6) Dendritic growth in alloys, (7) Screen saver science, (8) genetic programming.

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Nonrelativistic energies for the Be atom: Double-linked Hylleraas-CI calculation

Büsse

Kleindienst

Lüchow

1998

Int. J. Quant. Chem.

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Double-linked Hylleraas configuration-interaction calculation for the nonrelativistic ground-state energy of the Be atom

Cited by 11 publications

References 10 publications

Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations

Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations

Accelerating scientific discovery through computation and visualization II

Nonrelativistic energies for the Be atom: Double-linked Hylleraas-CI calculation

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