Abstract
Atoms subjected to extreme environmental conditions are of fundamental importance due to the modification of their electronic properties. In this work, we study the helium atom when immersed in a plasma environment. In order to describe the plasma medium, we use two models when solving the Schrödinger equation in a restricted Hartree–Fock approach: the Debye–Hückel screened (DHS) potential and a more general exponential-cosine screened Coulomb (ECSC) potential. The plasma length parameter, \(\lambda \), in both model potentials characterizes the plasma screening effects which cause an increase or decrease in the electronic properties of the helium atom. We report results for the total electronic ground state energy, orbital energy, dipole oscillator strengths, generalized oscillator strengths (GOS), mean excitation energy, electrostatic dipole polarizability, and electronic stopping cross section. We find that the ECSC plasma model produces a less bound system than the DHS plasma model at the same value of the screening length, \(\lambda \). However, the ECSC model potential has a stronger dipole transition from the 1s to the 2p and 3p states than the DHS model potential. Also, the ECSC potential predicts a higher static dipole polarizability than the DHS model potential, with a consequent lower mean excitation energy. We also find a larger GOS for the ECSC than for the DHS for the same momentum transfer at the same value of the screening length, \(\lambda \). Consequently, the ECSC mode potential produces a larger electronic stopping cross section than the DHS for the same \(\lambda \) and projectile velocity. In the limit of \(\lambda \rightarrow \infty \), we have excellent agreement with the free helium properties. These quantitative values for the electronic properties would be useful for the investigations of the atomic structure and collisions of helium atoms immersed in plasmas.
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This manuscript has no associated data or the data will not be deposited. [Authors’ comment: All data generated or analysed during this study are included in this published article.]
References
R.K. Janev, S. Zhang, J. Wang, Review of quantum collision dynamics in debye plasmas. Matt. Rad. Extrem. 1, 237–248 (2016)
G.J. Hatton, N.F. Lane, J.C. Weisheit, Inelastic electron-ion scattering in a dense plasma. J. Phys. B: At. Mol. Phys. 14(24), 4879–4888 (1981)
N.C. Deb, N.C. Sil, Electron impact excitation of positive ions in dense plasma. J. Phys. B At. Mol. Phys. 17(17), 3587–3591 (1984)
D. Salzmann, J. Stein, I.B. Goldberg, R.H. Pratt, Effect of nearest-neighbor ions on excited ionic states, emission spectra, and line profiles in hot and dense plasmas. Phys. Rev. A 44, 1270–1280 (1991)
F.A. Gutierrez, J. Diaz-Valdes, Effects of non-spherical screening for inelastic electron-ion scattering. J. Phys. B At. Mol. Opt. Phys. 27(3), 593–600 (1994)
R. Brandenburg, J. Schweinzer, S. Fiedler, F. Aumayr, H.P. Winter, Modelling of fast neutral li beams for fusion edge plasma diagnostics. Plasma Phys. Controll. Fusion 41(4), 471–484 (1999)
L.B. Zhao, Y.K. Ho, Influence of plasma environments on photoionization of atoms. Phys. Plasmas 11(4), 1695–1700 (2004)
W. Hong, Y.-D. Jung, Plasma-screening effects on direct 1s\(\rightarrow \)2p\(^\pm \) electron-ion collisional excitation rates in dense plasmas. Phys. Plasmas 3(6), 2457–2460 (1996)
J.-S. Yoon, Y.-D. Jung, Spherical versus nonspherical plasma-screening effects on semiclassical electron-ion collisional excitations in weakly coupled plasmas. Phys. Plasmas 3(9), 3291–3296 (1996)
U. Gupta, A.K. Rajagopal, Density functional formalism at finite temperatures with some applications. Phys. Rep. 87(6), 259–311 (1982)
B.L. Whitten, N.F. Lane, J.C. Weisheit, Plasma-screening effects on electron-impact excitation of hydrogenic ions in dense plasmas. Phys. Rev. A 29, 945–952 (1984)
M. Flannery, E. Oks, Plasma screening within rydberg atoms in circular states. Eur. Phys. J. D 47, 27 (2008)
L. Liu, J.G. Wang, R.K. Janev, Dynamics of \({\rm he}^{2+}+{\rm H}(1s)\) excitation and electron-capture processes in debye plasmas. Phys. Rev. A 77, 032709 (2008)
L. Liu, J.G. Wang, R.K. Janev, Dynamics of \({\rm he}^{2+}+{\rm H}(1s)\) ionization with screened coulomb interactions. Phys. Rev. A 77, 042712 (2008)
M.S. Pindzola, S.D. Loch, J. Colgan, C.J. Fontes, Electron-impact ionization of atoms in high-temperature dense plasmas. Phys. Rev. A 77, 062707 (2008)
A.C.H. Yu, Y.K. Ho, Stark shifts and widths of a hydrogen atom in debye plasmas. Phys. Plasmas 12(4), 043302 (2005)
S. Sahoo, Y.K. Ho, Photoionization of li and na in debye plasma environments. Phys. Plasmas 13(6), 063301 (2006)
S. Kar, Y.K. Ho, Photodetachment of the hydrogen negative ion in weakly coupled plasmas. Phys. Plasmas 15(1), 013301 (2008)
S. Paul, Y.K. Ho, Effects of debye plasmas on two-photon transitions in lithium atoms. Phys. Rev. A 78, 042711 (2008)
E. Hückel, P. Debye, The theory of electrolytes: I. Lowering of freezing point and related phenomena. Phys. Z 24, 185–206 (1923)
P.K. Shukla, B. Eliasson, Screening and wake potentials of a test charge in quantum plasmas. Phys. Lett. A 372(16), 2897–2899 (2008)
B. Saha, T.K. Mukherjee, P.K. Mukherjee, G.H.F. Diercksen, Variational calculations for the energy levels of confined two-electron atomic systems. Theoret. Chem. Acc. 108(5), 305–310 (2002)
S. Kar, Y.K. Ho, Bound states of helium atom in dense plasmas. Int. J. Quant. Chem. 106, 814–822 (2006)
A. Ghoshal, Y.K. Ho, Ground states of helium in exponential-cosine-screened coulomb potentials. J. Phys. B Atomic Mol. Opt. Phys. 42, 075002 (2009)
J.K. Saha, S. Bhattacharyya, T.K. Mukherjee, P.K. Mukherjee, \(^{1,3}d^o\) and \(^{1,3}p^e\) states of two electron atoms under debye plasma screening. J. Quant. Spectrosc. Radiat. Transf. 111(5), 675–688 (2010)
M.C. Zammit, D.V. Fursa, I. Bray, R.K. Janev, Electron-helium scattering in debye plasmas. Phys. Rev. A 84, 052705 (2011)
M.C. Zammit, D.V. Fursa, I. Bray, Electron scattering in a helium debye plasma. Chem. Phys. 398, 214–220 (2012)
S. Kar, Y. Wang, Z. Jiang, S. Li, K. Ratnavelu, Doubly-excited 1,3de resonance states of two-electron positive ions li+ and be2+ in debye plasmas. Phys. Plasmas 21(1), 012105 (2014)
H. Xiao-Qing, Y. Wang, Z. Jiang, P. Jiang, S. Kar, Doubly excited 3pe resonance states of two-electron positive ions in debye plasmas. Phys. Plasmas 22(11), 112107 (2015)
Y.-C. Lin, C.-Y. Lin, Y.K. Ho, Spectral/structural data of helium atoms with exponential-cosine-screened coulomb potentials. Int. J. Quantum Chem. 115(13), 830–836 (2015)
Y.-C. Lin, T.-K. Fang, Y.K. Ho, Quantum entanglement for helium atom in the debye plasma. Phys. Plasmas 2(3), 32113 (2015)
K.D. Sen, J. Katriel, H.E. Montgomery, A comparative study of two-electron systems with screened coulomb potentials. Ann. Phys. 397, 192–212 (2018)
H.E. Montgomery, K.D. Sen, J. Katriel, Critical screening in the one- and two-electron yukawa atoms. Phys. Rev. A 97, 022503 (2018)
S. Kar, Y.-S. Wang, Y.K. Ho, Critical stability for two-electron ions with yukawa potentials and varying \(z\). Phys. Rev. A 99, 042514 (2019)
Z. Wang, P. Winkler, Pair-function calculations for two-electron systems in model plasma environments. Phys. Rev. A 52, 216–220 (1995)
P.K. Mukherjee, J. Karwowski, G.H.F. Diercksen, On the influence of the debye screening on the spectra of two-electron atoms. Chem. Phys. Lett. 363(3), 323–327 (2002)
S. Sen, P. Mandal, P.K. Mukherjee, B. Fricke, Hyperpolarizabilities of one and two electron ions under strongly coupled plasma. Phys. Plasmas 20(1), 013505 (2013)
P. Jiang, S. Kar, Y. Zhou, Doubly-excited states of two-electron systems in lorentzian astrophysical plasmas. Few-Body Syst. 54(11), 1911–1919 (2018)
S.K. Chaudhuri, P.K. Mukherjee, B. Fricke, Hyperpolarizability of two electron atoms under exponential cosine screened coulomb potential. Phys. Plasmas 22(12), 123120 (2015)
S. Kar, Y.-S. Wang, Y. Wang, Z. Jiang, Tune-out wavelengths for helium atom in plasma environments. Phys. Plasmas 23(8), 82119 (2016)
M.K. Bahar, A. Soylu, Confinement control mechanism for two-electron hulthen quantum dots in plasmas. J. Phys. B At. Mol. Opt. Phys. 51(10), 105701 (2018)
M.K. Bahar, A. Soylu, Laser-driven two-electron quantum dot in plasmas. Phys. Plasmas 25(6), 062113 (2018)
M.K. Bahar, A. Soylu, Two-electrons quantum dot in plasmas under the external fields. Phys. Plasmas 25(2), 022106 (2018)
Z.-B. Chen, K. Ma, H. Hong-Wei, K. Wang, Relativistic effects on the energy levels and radiative properties of he-like ions immersed in debye plasmas. Phys. Plasmas 25(7), 72120 (2018)
S. Kar, Y.K. Ho, Oscillator strengths and polarizabilities of the hot-dense plasma-embedded helium atom. J. Quant. Spectrosc. Radiat. Transf. 109(3), 445–452 (2008)
S. Kar, Y.K. Ho, Multipole polarizabilities of helium and the hydrogen negative ion with coulomb and screened coulomb potentials. Phys. Rev. A 80, 062511 (2009)
Y.Y. Qi, J.G. Wang, R.K. Janev, Static dipole polarizability of hydrogenlike ions in debye plasmas. Phys. Rev. A 80, 032502 (2009)
Z. Jiang, S. Kar, Y.K. Ho, Polarizabilities of two-electron positive ions with screened coulomb potentials. Phys. Rev. A 84, 012504 (2011)
L.-N. Ning, Y.-Y. Qi, Static electric dipole polarizability of lithium atoms in debye plasmas. Chin. Phys. B 21(12), 123201 (2012)
S. Kar, Y.-S. Wang, Y. Wang, Y.K. Ho, Polarizability of negatively charged helium-like ions interacting with coulomb and screened coulomb potentials. Int. J. Quant. Chem. 118(7), 25515 (2018)
S.N. Ketkar, R.A. Bonham, Experimental determination of the moments of the generalized oscillator strength distribution of he. J. Chem. Phys. 84(11), 6091–6094 (1986)
A.K. Bhatia, R.J. Drachman, Properties of two-electron systems in an electric field. Can. J. Phys. 75(1), 11–18 (1997)
Plasma Science Committee, (ed.). Plasma Science : From Fundamental Research to Technological Applications. National Academies Press, Washington, D.C., 1st edn, (1995)
A.N. Sil, S. Canuto, P.K. Mukherjee, Spectroscopy of confined atomic systems: Effect of plasma. Adv. Quant. Chem. 58, 115–175 (2009)
Y.Y. Qi, J.G. Wang, R.K. Janev, Photoionization of hydrogen-like ions in dense quantum plasmas. Phys. Plasm. 24, 062110 (2017)
L. Guang, J.L. Rong, Z.L. Zhu, J. Ma, Y.K. Ho, Accurate computation of screened coulomb potential integrals in numerical hartree-fock programs. Comput. Phys. Commun. 224, 217–227 (2019)
R. Cabrera-Trujillo, S.A. Cruz, Confinement approach to pressure effects on the dipole and the generalized oscillator strength of atomic hydrogen. Phys. Rev. A 87, 012502 (2013)
C. Martínez-Flores, R. Cabrera-Trujillo, Dipole and generalized oscillator strength derived electronic properties of an endohedral hydrogen atom embedded in a debye-hückel plasma. Matter Radiat. Extremes 3(5), 227–242 (2018)
C. Martínez-Flores, R. Cabrera-Trujillo, Dipole sum rules of a hydrogen atom in a debye-hückel plasma. Eur. Phys. J. D 73, 191 (2019)
C. Martínez-Flores, Generalized oscillator strengths for the ground state [2p63s]2s of sodium atom embedded in a plasma medium. Chem. Phys. 535, 110759 (2020)
H.A. Bethe, R. Jackiw (eds.), Intermediate Quantum Mechanics, 3rd edn. (Westview Press, New York, 1997)
H. Bethe, Zur theorie des durchgangs schneller korpuskularstrahlen durch materie. Ann. Phys. 397(3), 325–400 (1930)
M. Inokuti, Inelastic collisions of fast charged particles with atoms and molecules-the bethe theory revisited. Rev. Mod. Phys. 43, 297–347 (1971)
H. Friedrich, Theoretical Atomic Physics, 3rd edn. (Springer-Verlag, Berlin, 2006)
J. Oddershede, J.R. Sabin, Orbital and whole-atom proton stopping power and shell corrections for atoms with z\(leq\)36. At. Data Nucl. Data Tables 31(2), 275–297 (1984)
L.U. Ancarani, K.V. Rodriguez, Correlated expansions of \(n^{1}s\) and \(n^{3}s\) states for two-electron atoms in exponential cosine screened potentials. Phys. Rev. A 89, 012507 (2014)
T.D. Young, R. Vargas, J. Garza, A Hartree-Fock study of the confined helium atom: local and global basis set approaches. Phys. Lett. A 380, 712–717 (2016)
A.F. Duarte-Alcaráz, M.A. Martínez-Sánchez, M. Rivera-Almazo, R. Vargas, R.A. Rosas-Burgos, J. Garza, Testing one-parameter hybrid exchange functionals in confined atomic systems. J. Phys. B At. Mol. Opt. Phys. 52, 135002 (2019)
A.W. King, A.L. Baskerville, H. Cox, Hartree-fock implementation using a laguerre-based wave function for the ground state and correlation energies of two-electron atoms. Philos. Trans. R. Soc. A Math. Phys. Eng. Sci. 376(2115), 20170153 (2018)
I. Nasser, M. Zeama, A. Abdel-Hady, The nonadditive entropy for the ground state of helium-like ions using hellmann potential. Mol. Phys. 118(3), 1612105 (2020)
M. Zeama, I. Nasser, Tsallis entropy calculation for non-coulombic helium. Physica A 528, 121468 (2019)
C. Martínez-Flores, The information theory of the helium atom in screened coulomb potentials. Int. J. Quant. Chem. 5, 26529 (2020)
J. Li, N.D. Drummond, P. Schuck, V. Olevano, Comparing many-body approaches against the helium atom exact solution. SciPost Phys. 6, 40 (2019)
A.W. Weiss, Oscillator strengths for the helium isoelectronic sequence. J. Res. Notl. Bureau Stand. A Phys. Chem. 71, 163 (1967)
Y.-K. Kim, M. Inokuti, Generalized oscillator strengths of the helium atom. i. Phys. Rev. 175, 176–188 (1968)
K.Z. Xu, R.F. Feng, S.L. Wu, Q. Ji, X.J. Zhang, Z.P. Zhong, Y. Zheng, Absolute generalized oscillator strengths of \(2^{1}\)s and \(2^{1}\)p excitations of helium measured by angle-resolved electron-energy-loss spectroscopy. Phys. Rev. A 53, 3081–3086 (1996)
J. Mitroy, M.S. Safronova, C.W. Clark, Theory and applications of atomic and ionic polarizabilities. J. Phys. B 43(20), 202001 (2010)
J. L. Dehmer, Mitio. Inokuti, R. P. Saxon, Systematics of moments of dipole oscillator-strength distributions for atoms of the first and second row. Phys. Rev. A, 12:102–121, (Jul 1975)
P. Schwerdtfeger, J.K. Nagle, 2018 table of static dipole polarizabilities of the neutral elements in the periodic table. Mol. Phys. 5, 1–26 (2018)
H. Baumgart, W. Arnold, H. Berg, E. Huttel, G. Clausnitzer, Proton stopping powers in various gases. Nucl. Instrum. Methods Phys. Res. 204(2), 597–604 (1983)
F. Besenbacher, H.H. Andersen, P. Hvelplund, H. Knudsen, Stopping power of swift hydrogen and helium ions in gases. Matematisk-Fysiske Meddelelser 40(3), 1–39 (1979)
H.K. Reynolds, D.N.F. Dunbar, W.A. Wenzel, W. Whaling, The stopping cross section of gases for protons, 30–600 kev. Phys. Rev. 92, 742–748 (1953)
J.E. Brolley, F.L. Ribe, Energy loss by 8.86-mev deuterons and 4.43-mev protons. Phys. Rev. 98, 1112–1117 (1955)
G. Reiter, N. Kniest, E. Pfaff, G. Clausnitzer, Proton and helium stopping cross sections in h2, he, n2, o2, ne, ar, kr, xe, ch4 and co2. Nucl. Instrum. Methods Phys. Res. Sect. B Beam Interact. Mater. Atoms 44(4), 399–411 (1990)
R. Golser, D. Semrad, Observation of a striking departure from velocity proportionality in low-energy electronic stopping. Phys. Rev. Lett. 66, 1831–1833 (1991)
F. Raiola, G. Gyürky, M. et al., Aliotta. Stopping power of low-energy deuterons in 3he gas. Eur. Phys. J. A Hadrons Nuclei 10, 478–491 (2001)
A. Schiefermüller, R. Golser, R. Stohl, D. Semrad, Energy loss of hydrogen projectiles in gases. Phys. Rev. A 48, 4467–4475 (1993)
D. Jedrejcic, U. Greife, Energy loss of low energy hydrogen and helium ions in light gases. Nucl. Instrum. Methods Phys. Res. Sect. B 428, 1–8 (2018)
S. Qin, C. Chan, J. Browning, S. Meassick, Charge transfer cross section of he+ in collisional helium plasma using the plasma immersion ion implantation technique. J. Appl. Phys. 74(3), 1548–1552 (1993)
Acknowledgements
M.F.-C. thanks CONACyT for the postdoctoral fellowship through the project FC-2016/2412 as well as to the hospitality of the Chemistry Department at UAM-I. R.C.-T. gratefully acknowledges support from DGAPA-PAPIIT IN-111-820 as well as to DGAPA-PASPA program for the sabbatical year at the University of Heidelberg where this work was partially realized.
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Topical Issue: Atoms and Molecules in a Confined Environment. Guest editors: C.N. Ramachandran, Vincenzo Aquilanti, Henry Ed Montgomery, N. Sathyamurthy.
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Martínez-Flores, C., Cabrera-Trujillo, R. Dipole and generalized oscillator strengths-dependent electronic properties of helium atoms immersed in a plasma. Eur. Phys. J. D 75, 133 (2021). https://doi.org/10.1140/epjd/s10053-021-00146-z
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DOI: https://doi.org/10.1140/epjd/s10053-021-00146-z