[PDF]    https://doi.org/10.3952/physics.v58i3.3810

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 58, 221–231 (2018)
THEORETICAL STUDY OF 4p5nln'l'LSJ STATES OF Sr ION EXCITED BY ELECTRON IMPACT ON Sr ATOM
Alicija Kupliauskienė
Institute of Theoretical Physics and Astronomy, Vilnius University, Saulėtekio 3, 10257 Vilnius, Lithuania
E-mail: tfai@tfai.vu.lt
Received 10 January 2018; revised 15 March 2018; accepted 21 June 2018

Calculations of energy levels and electron-impact excitation cross sections of the Auger autoionizing states 4p5nln'l' (nl = 4d, 5s, 5p; n'l'= 4d, 5s, 5p, 5d, 6s, 6p, 6d, 7s, 7p) of Sr ion were performed. A large-scale configuration interaction method on the basis of the solutions of Dirac–Fock–Slater equations was used. The cross sections of electron-impact simultaneous ionization and excitation, and Auger decay of the electron-impact excited states of Sr atom to the 4p-core excited autoionizing states of Sr ion were calculated for the first time and used to estimate the intensity of ejected electron lines. Tentative identification of the Auger electron lines of Sr ion registered in a number of experiments is presented.
Keywords: electronic structure of atoms and molecules, theory, autoionization, atomic excitation and ionization
PACS: 31.15.-p, 32.80.Zb, 34.80.Dp

Sr JONO 4p5nln'l'LSJ BŪSENŲ, SUŽADINANT Sr ATOMĄ ELEKTRONAIS, TYRIMAS
Alicija Kupliauskienė

Vilniaus universiteto Teorinės fizikos ir astronomijos institutas, Vilnius, Lietuva

Sr jono 4p5nln'l'LSJ būsenos su vakansija 4p sluoksnyje registruojamos eksperimentuose, kuriuose sužadinamos Sr atomo būsenos su vakansija šiame sluoksnyje. Tokiuose eksperimentuose jos gali būti užpildytos trimis būdais: tiesioginės jonizacijos į 4p55s2 2P1/2,3/2 būsenas, sužadinimo ir jonizacijos vienu metu į 4p5nln'l'LS(J = 1/2, 3/2) būsenas ir suyrant Sr atomo 4p5nln'l'n''l''LSJ būsenoms į Sr jono 4p5nln'l'LSJ būsenas. Darbe apskaičiuoti šių procesų skerspjūviai bei Sr+ jono 4p5nln'l' ir Sr atomo 4p5nln'l'n''l'' konfigūracijų lygmenų energijos, autojonizacijos tikimybės ir sužadinimo elektronais skerspjūviai konfigūracijų superpozicijos metodu. Į reliatyvistines pataisas atsižvelgta ieškant radialiųjų banginių funkcijų Dirako, Foko ir Sleiterio artinyje.
Sr atomo lygmenų energijos, banginių funkcijų, transformuotų iš jjJ į LSJ judesio kiekio momentų jungimo ryšį, skleidimo koeficientai panaudoti 4p5nln'l'LSJ teoriniams lygmenims klasifikuoti. Didžiausi sužadinimo ir jonizacijos vienu metu bei sužadinimo ir autojonizacijos skerspjūviai, kuriems proporcingi išspinduliuotų Sr jono linijų intensyvumai, panaudoti eksperimente užregistruotoms išlėkusių elektronų 28 linijoms identifikuoti.

References / Nuorodos

[1] C. Banahan, J.T. Costello, D. Kilbane, and P. van Kampen, 4p-inner-shell and double-excitation spectrum of Sr II, Phys. Rev. A 79(2), 022509 (2009),
https://doi.org/10.1103/physreva.79.022509
[2] D. Rassi and K.J. Ross, The ejected-electron spectrum of barium vapour autoionizing and Auger levels excited by 20–500 eV electrons, J. Phys. B 13(23), 4683–4694 (1980),
https://doi.org/10.1088/0022-3700/13/23/024
[3] W. Schmitz, B. Breuckmann, and W. Mehlhorn, Low-energy electron spectra of atomic Ca and Sr excited by 2 keV electrons, J. Phys. B 9(16), L493–L497 (1976),
https://doi.org/10.1088/0022-3700/9/16/007
[4] M.D. White, D. Rassi, and K.J. Ross, The ejected electron spectrum of strontium vapour autoionizing and Auger levels excited by 23.5 and 500 eV electrons, J. Phys. B 12(2), 315–323 (1979),
https://doi.org/10.1088/0022-3700/12/2/020
[5] M.W.D. Mansfield and G.H. Newsom, The Sr I absoption spectrum in the vacuum ultraviolet: excitation of the 4p-subshell, Proc. R. Soc. London A 377, 431–448 (1981),
https://doi.org/10.1098/rspa.1981.0134
[6] A.A. Borovik, I.S. Aleksakhin, V.F. Bratsev, and A.V. Kupliauskiene, Excitation and electron decay of the autoionizing states of the rare earth atoms: Strontium, Opt. Spektrosk. 53(6), 976–980 (1982) [in Russian]
[7] S.M. Kazakov and O.V. Khristoforov, Electron spectra from autoionizing states of strontium and calcium excited by low- and intermediate-energy electrons, Sov. Phys. JETP 61(4), 656–664 (1985)
[8] V. Hrytsko, G. Kerevičius, A. Kupliauskienė, and A. Borovik, The 5p autoionization spectra of Ba atoms excited by electron impact: identification of lines, J. Phys. B 49, 145201 (2016),
https://doi.org/10.1088/0953-4075/49/14/145201
[9] A. Borovik, V. Vakula, and A. Kupliauskienė, The 4p6-core excited autoionizing states of strontium: classification and excitation dynamics, Lith. J. Phys. 47(2), 129–135 (2007),
https://doi.org/10.3952/lithjphys.47203
[10] A. Kupliauskienė, G. Kerevičius, V. Borovik, I. Shafranyosh, and A. Borovik, The energy structure and decay channels of the 4p6 shell excited states in Sr, J. Phys. B 50, 225201 (2017),
https://doi.org/10.1088/1361-6455/aa90df
[11] S.H. Tersigni, Core-excited Nanoparticles and Methods of Their Use in the Diagnosis and Treatment of Disease, Patent US8197471 B1, WO212112547A1 (2012)
[12] J. Nienhaus, O.I. Zatsarinny, and W. Mehlhorn, Experimental and theoretical Auger and autoionization spectra for electron-impact on laser-excited Ba atom, Phys. Essays 13(2–3), 307–324 (2000),
https://doi.org/10.4006/1.3028825
[13] A. Borovik, V. Roman, and A. Kupliauskienė, The 4p6 autoionization cross section of Rb atoms excited by low-energy electron impact, J. Phys. B 45(4), 045204 (2012),
https://doi.org/10.1088/0953-4075/45/4/045204
[14] J.P. Connerade, S.J. Rose, and I.P. Grant, Two-step autoionization and double ionization anomaly in Ba I, J. Phys. B 13(2), L53–L55 (1979),
https://doi.org/10.1088/0022-3700/12/2/004
[15] R.D. Cowan, The Theory of Atomic Structure and Spectra (University of California Press, Berkeley, CA, 1981)
[16] J.E. Hansen, The structure of the autoionizing p5ds configurations in Ma II, Ca II, Sr II and Ba II and interpretation of electron impact cross sections in these ions, J. Phys. B 8(17), 2759–2770 (1975),
https://doi.org/10.1088/0022-3700/8/17/007
[17] C. Froese Fischer, General Hatree-Fock program, Comput. Phys. Commun. 43(3), 355–365 (1987),
https://doi.org/10.1016/0010-4655(87)90053-1
[18] A. Kupliauskienė, On the application of relaxed-orbital and sudden perturbation approximations for photoionization of atoms, J. Phys. B 34, 345–361 (2001),
https://doi.org/10.1088/0953-4075/34/3/312
[19] M.F. Gu, The flexible atomic code, Can. J. Phys. 86(5), 675–689 (2008),
https://doi.org/10.1139/p07-197
[20] O. Zatsarinny (2016) [private communication]
[21] A. Kupliauskienė, A general expression for the excitation cross-section of polarized atoms by polarized electrons, Phys. Scripta 75(4), 524–530 (2007),
https://doi.org/10.1088/0031-8949/75/4/026
[22] A. Kupliauskienė and V. Tutlys, Properties of Auger electrons following excitation of polarized atoms by polarized electrons, Nucl. Instrum. Methods B 267(2), 263265 (2009),
https://doi.org/10.1016/j.nimb.2008.10.039
[23] G. Kerevičius and A. Kupliauskienė, Classification of the 5p5nln’l’LSJ energy levels of Cs excited by 30 eV electrons, Lith. J. Phys. 55(2), 84 (2015),
https://doi.org/10.3952/physics.v55i2.3098
[24] S. Kour and R. Srivastava, Excitation of the lowest autoionizing np5(n+1)s2 2P3/2, 1/2 states of Na (n = 2), K (n = 3), Rb (n = 4) and Cs (n = 5) by electron impact, J. Phys. B 32(10), 2323–2342 (1999),
https://doi.org/10.1088/0953-4075/32/10/303