Configuration Interaction in Simple Atomic Systems

Weiss, A. W.

doi:10.1103/physrev.122.1826

Cited by 451 publications

(139 citation statements)

References 18 publications

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…The partial wave expansion here was carried through i-orbitals, i.e., 1 = 6, and all exponential parameters were determined by minimizing the ground state energy for these ions. After some numerical experimentation, a double [ set was decided on for each symmetry, with principal quantum numbers for each [ running up to some maximum, much like the bases recently used for helium r,, calculations (2, 3) and those used in some of the earliest of the CI calculations (13). These calculations recover better than 99% of the correlation energy of the ground state of the helium-like ions, which should be adequate to represent core correlation contributions to the threeelectron atom ionization and excitation energies.…”

Section: Description Of Calculations and Energy Resultsmentioning

confidence: 99%

The calculation of atomic oscillator strengths: the lithium atom revisited

Weiss¹

1992

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

interaction calculations have been done for the ground and first excited states of neutral lithium and singly ionized beryllium. While the calculations reproduce the ionization and excitation energies to within 3 cm-I for Li and 10 cm-I for ~e ' , the main purpose of this work is the accurate evaluation of the 2s-2p resonance line oscillator strength. The calculated value of 0.7478 agrees to within less than 1% with the very accurate laser excitation lifetime measurement of 0.7416 * 0.0012. However, internal consistency checks of the accuracy of these calculations suggest that more precise calculations are unlikely to reduce this discrepancy significantly. Furthermore, when placed together with other independent calculations that should be of comparable, if not better, accuracy, all theoretical predictions strongly indicate an f-value of 0.7475 * 0.0010, which differs from the experiment by 4 experimental standard deviations.Key words: configuration interaction, correlation, oscillator strength.A. W. W~rss. Can. J . Chem. 70, 456 (1992). On a effectut des calculs Ctendus d'interactions de configuration de I'ttat fondamental et du premier Ctat excite du lithium neutre et du beryllium mono-ionisC. Alors que les calculs permettent de reproduire les energies d'ionisation et d'excitation a moins de 3 cm-' pour le Li et a moins de 10 cm-' pour le Be+, le but principal de ce travail est d7Cvaluer d'une faqon precise la force de l'oscillateur de la raie de resonance 2s-2p. La valeur calculee, 0,7478, est a moins de 1% de la valeur tres precise, 0,7416 * 0,0012, obtenue par des mesures de temps de vie d'excitation au laser. Toutefois, des evaluations d'auto-coherence de la precision de ces calculs laissent croire que des calculs plus precis ne reduiraient pas cette difference d'une faqon significative. De plus, lorsqu'on utilise cette valeur avec celles obtenues par d'autres calculs independants d'une precision au moins semblable, si non meilleure, on en deduit que toutes les predictions thkoriques indiquent fortement que la valeur de f est Cgale a 0,7475 2 0,0010 qui differe de la valeur experimentale par 4 kcarts types expkrimentaux.

show abstract

Section: Description Of Calculations and Energy Resultsmentioning

confidence: 99%

The calculation of atomic oscillator strengths: the lithium atom revisited

Weiss¹

1992

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Finally, we considered Lamb corrections [29]. For the two-and four-isoelectronic series, we took the values reported by Clementi [30] and those of Weiss [31] for H-and Li--.…”

Section: Resultsmentioning

confidence: 99%

Applicability to atoms of a large set of correlation energy functinals

San‐Fabián

Moscardó

Pérez‐Jordá

1994

Int J of Quantum Chemistry

View full text Add to dashboard Cite

An extensive study of the application of a large set of correlation energy functionals to atomic systems is presented. Hartree-Fock densities and, sometimes, generalized-valence-bond wave functions are used. The functionals have been grouped into four sets: (I) local density and local spin density, (11) local spin density with self-interaction correction, (111) local spin density with gradient correction, and (IV) methods found on the correlation factor approach. In this bench mark, we report the results of calculations made for the ground states of the first and second rows, their anions and cations, and the two-and four-isoelectronic series. 0

show abstract

“…and of the spin-geminals &, all being degenerate. Equations (12), (18), and (19) yield the link between the total and pair correlation factors, which is All the above formalism, which has been written for an exact wave function v', is still valid for a truncated CI wave function, including only part of the total correlation energy. This is due to the fact that Eq.…”

Section: )mentioning

confidence: 99%

Modified bielectronic potential method for correlation energy

Ruelle

1979

Int J of Quantum Chemistry

View full text Add to dashboard Cite

AbstractsLowdin's correlation potential formalism has been used to define a modified bielectronic potential, allowing one to calculate the exact electronic energy, given the Hartree-Fock wave function. This modified potential is in principle peculiar to each electronic system, and is defined by a correlation factor depending on the interelectronic distance r I 2 . The explicit calculation of the correlation factor has been performed for some two-electron atoms, in the 1's and 23S states, and for the beryllium atom. Examination of the results so obtained leads us to conclude in favor of the nonexistence of a universal modified bielectronic potential.Le formalisme du potentiel de corrklation de Lowdin a CtC utilisk pour dkfinir un potentiel bielectronique modifit, permettant de calculer I'tnergie tlectronique exacte au moyen de la fonction d'onde Hartree-Fock du systeme envisagk. Le potentiel modifit est, en principe, propre a chaque systeme tlectronique, et s'exprime au moyen d'un facteur de corrklation, fonction de la distance intertlectronique rI2. Les rtsultats du calcul explicite du facteur de corrtlation de quelques atomes bitlectroniques, dans les Ctats 1's et z3S, et de I'atome de bkryllium, sont prtsentts dans cet article. Leur examen nous amkne a conclure a la non-existence d'un potentiel bielectronique modifik universel.Lowdin's Formalismus zum Korrelationspotential wurde hier benutzt, um ein verandertes bielektronisches Potential zu beschreiben, das es ermoglicht, die genaue elektronische Energie mittels der Hartree-Fock-Wellenfunktioneines bestimmten Systemszu berechnen. DiesesverandertePotential ist, im Prinzip, jedem Elecktronensystem eigen, und ist bestimmt durch einen Korrelationsfaktor abhangig von der interelektronischen Distanz r12. Ausdriickliche Berechnungen des Korrelationsfaktors einiger bielektronischen Atorne im Zustand 1's und 23S, und des Berylatoms, werden hier gezeigt. Die Beobachtung dieser Resultate bringt uns zur Scblussfolgerung der Nicht-Existenz eines universalen veranderten Potentials.

show abstract

Configuration Interaction in Simple Atomic Systems

Cited by 451 publications

References 18 publications

The calculation of atomic oscillator strengths: the lithium atom revisited

The calculation of atomic oscillator strengths: the lithium atom revisited

Applicability to atoms of a large set of correlation energy functinals

Modified bielectronic potential method for correlation energy

Contact Info

Product

Resources

About