Electron-impact excitation of the Mg atom from the ground and metastable states:<i>R</i>-matrix calculation with pseudostates

Gedeon, Viktor; Lengyel, V.; Zatsarinny, Oleg; Kocher, Carl A.

doi:10.1103/physreva.59.2016

Cited by 17 publications

(18 citation statements)

References 37 publications

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“…From the theoretical standpoint Mg is very interesting because this is a relatively small atom in which the ground state and the excited states can be well described within the LS coupling scheme. However, Mg very often shows significantly different behavior when compared to other similar systems ͑e.g., Mg as a target in electron-impact processes 29,30 ͒. Therefore, the purpose of the present work is to use the VU-CCSD/R method, which has been successfully applied to the Be-like systems, 28 to calculate the ground-state energy, ionization potential, and some excitation energies of the Mg atom.…”

Section: Introductionmentioning

confidence: 99%

Application of the intermediate Hamiltonian valence-universal coupled-cluster method to the magnesium atom

Malinowski

Meissner

Nowaczyk

2002

The Journal of Chemical Physics

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Renormalized coupled-cluster methods exploiting left eigenstates of the similarity-transformed HamiltonianPerformance of the general-model-space state-universal coupled-cluster methodThe atomically oriented valence-universal coupled-clusters method in the intermediate Hamiltonian formulation with one-and two-body part͑s͒ included in the cluster operator ͑VU-CCSD/R͒ is applied to describe the ground state and some excited states of the Mg atom. Two Slater-type orbitals ͑STO͒ basis sets are employed to see the effect of the basis set on the results. In addition to that, several complete model spaces are used in the calculation starting with (3s,3p) and ending with (3s,3p,3d,4s,4p) orbitals as active. It has been found that the quality of the description of the ground-and excited states depends on the STO basis set used in the calculation. In order to obtain reliable excitation energies, special attention has been paid to the construction of well-balanced basis sets in which functions necessary for adequate description of both the ground state and excited states under consideration are included. Therefore, in spite of the moderate size of the orbital basis, our results compare quite well in terms of the total energy as well as in energy differences with results of other methods which, in some cases, use significantly larger basis sets.

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Section: Introductionmentioning

confidence: 99%

Application of the intermediate Hamiltonian valence-universal coupled-cluster method to the magnesium atom

Malinowski

Meissner

Nowaczyk

2002

The Journal of Chemical Physics

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“…Хвильові функції мішені були отримані накладанням конфігурацій у рамках методу Хартрі-Фока в LS-зв'язку. Метод розрахунку був попередньо відтестований на інших лужноземельних атомах: Sr [2] та Mg [3,4], а також іонах Zn + [5] та Cd + [6]. Розраховані в [1] перерізи демонструють яскраво виражену резонансну структуру, яка дає помітний вклад у повні перерізи збудження.…”

Section: вступunclassified

“…Дані R-матричні розрахунки ІП розсіяння проведені з врахуванням 38 станів мішені: 16 фізичних станів (розташованих в області енергій до 3.5 еВ), з експериментальними енергіями, та 22 псевдостанів з енергіями, що знаходяться поблизу порогу іонізації та в суміжному континуумі (по два псевдо-стани для кожного терму мішені, який був урахований при розв'язанні). Псевдостани включалися в розклад сильного зв'язку для того, щоб: а) компенсувати ефект від тих зв'язаних та неперервних станів мішені, які не були включені в розклад сильного зв'язку, б) контролювати ефекти нефізичних резонансів, як це було детально обговорено для e−Mg у [3,4] та e−Cd + у [6]. Фізичні стани, включені в наші розрахунки, як зазначалося вище, наведені на Рис.…”

Section: б) розрахунки розсіянняunclassified

Inelastic electron scattering from excited barium atoms

Бандурина¹,

Гедеон²

2018

Sci.Herald.Uzh.Univ.Ser.Phys

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У рамках R-матричного методу проведені розрахунки інтегральних пер ерізів (ІП) збудження низькоенергетичними електронами атомів барію з м етастабільних станів 6s5d 3 D та 6s5d 1 D. Сили зіткнень розраховані в наближенні сильного зв'язку каналів із урахуванням 38 термів. Останні включали 16 фізич них станів мішені та 22 псевдостани, нарахованих в LS-зв'язку. Отримані у наближенні R-матриці з псевдостанами перерізи проявляють яскраво вир ажену резонансну структуру. Проведено порівняння розрахованих ІП розсіяння е−Ва з наявними експериментальними даними. Отримано добре узгодження теорії з експериментом. Ключові слова: атом Ba, псевдостани, розсіяння електронів, сильний зв'язо к каналів, метод R-матриці, інтегральні перерізи розсіяння.Background: Progress in the field of physics of electron-atom collisions is depen dent on two main factors: a) the availability of new studies of individual atomic s y stems; b) the clarify, systematize and generalize of results, obtained in previou s studies. In the last two decade we, together with co-authors, investigate in detail the elastic and inelastic electron scattering on neutral atomic systems Mg, Ba, Sr, Ca, Si, F, Al, and B. The purpose of this paper is to systematize and summarize the res u lt s o f studies of Ba atom, and is to continue the investigation of t h e s cat terin g in t egral cross sections of electrons on the excited barium atom, begun in our previous work. Methods: The atomic structure for Ba, as well as the excitation cro ss s ectio ns fo r e−Ba scattering processes were obtained by the R-matrix with pseudostates method . The multiconfiguration Hartree-Fock method with orthogonal orbital sets was e mployed for an accurate representation of the targets wave functions. The clo se co upling expansions include 39 term: 16 spectroscopic states of neutral bariu m an d 22 pseudostates. The scattering calculations was then carried out in the same way as in standard R-matrix calculations. Results: The integral cross sections for the scattering of low-energy elect rons b y a barium atom in the excited states 6s5d 3 D and 6s5d 1 D are calculated. The calculations were carried out in the R-matrix approximation with pseudostates. Th e co llision strengths were calculated in the close coupling channels approximation with allowance for 38 terms. The latter include 16 physical states of the target and 22 pseudostates accumulated in the LS-coupling. The cross sections obtained in the Rmatrix approximation exhibit a pronounced resonance structure. A comparison was made of the calculated ICS scattering e-Ba with the available experimental d at a. A good agreement between the theory and experiment was obtained. Conclusions: For the e-Ba collisions were the scattering cross-sections calculat ed. All transitions from the excited 6s5d 3 D and 6s5d 1 D states of the Ba atom to the 15 lowest excited levels were considered. The energy dependences of t h e IСS o n t h e type of spectral transition in the Ba atom were discussed.

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“…This problem has been recently examined by Bartschat and Sadeghpour [14] and by Gedeon et al [15] using R-matrix methods. However, when attempting to verify their results using the CCC method, we found unexpected difficulties in obtaining convergent results.…”

Section: Low-energy Electron-magnesium Elastic Scatteringmentioning

confidence: 99%

Various problems in electron-atom collision theory

Bray¹,

Bartschat²,

Fursa³

et al. 2003

AIP Conference Proceedings

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Abstract. We outline progress in a broad range of research projects that are currently being undertaken in our group. These include the formulation of ionisation amplitudes in Coulomb fewbody problems, a new convergent close-coupling implementation for electron-helium collisions, elastic electron-magnesium scattering at very low energies, and the calculation of electron-cesium spin asymmetries and differential cross sections.

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Electron-impact excitation of the Mg atom from the ground and metastable states:R-matrix calculation with pseudostates

Cited by 17 publications

References 37 publications

Application of the intermediate Hamiltonian valence-universal coupled-cluster method to the magnesium atom

Application of the intermediate Hamiltonian valence-universal coupled-cluster method to the magnesium atom

Inelastic electron scattering from excited barium atoms

Various problems in electron-atom collision theory

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