Absolute electron impact emission cross section of the He+22P to 12S line at 304 AA produced by simultaneous ionisation-excitation

Forand, J. Luc; Becker, K.; McConkey, J W

doi:10.1088/0022-3700/18/7/020

Cited by 55 publications

(41 citation statements)

References 17 publications

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“…6. The time-dependent close-coupling results are shown as filled squares, and lie between the absolute experimental measurements [18,19] and the hybrid distorted-wave/ R-matrix calculations [17]. Finally, total double ionization FIG.…”

Section: ͑21͒mentioning

confidence: 55%

“…For single ionization, leaving He + in the 2l excited states, we can compare to hybrid calculations [16,17], in which the scattered electron is treated by perturbative distorted-wave methods and the inner electrons are treated by a nonperturbative R-matrix method. In the case of single ionization, leaving He + in the 2p excited state, we can also compare to absolute experimental measurements [18,19]. For double ionization, we can compare to hybrid calculations [20], in which the scattered electron is treated in the plane-wave Born approximation and the inner electrons are treated using perturbation theory to connect correlated initial and final states, and to absolute experimental measurements [15].…”

Section: Introductionmentioning

confidence: 99%

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Electron-impact single and double ionization of helium

et al. 2004

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Electron-impact ionization cross sections for helium are calculated using time-dependent close-coupling theory. The total wave function for the three electron system is expanded in nine dimensions, where three dimensions are represented on a radial lattice and a coupled channels expansion is used to represent the other six dimensions. Collision cross sections are obtained by t → ϱ projection onto fully antisymmetric spatial and spin functions, with care as to orthogonality of different representations. Cross sections are also obtained using time-independent first-and second-order perturbative distorted-wave theory. Total cross sections are calculated at incident energies above the double ionization threshold for electron-impact single ionization leaving He + in the 1s, 2s, and 2p states and for electron-impact double ionization. Both the single ionization cross section, leaving He + in the 1s ground state, and the double ionization cross section are in excellent agreement with previous absolute experimental measurements.

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Section: ͑21͒mentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Electron-impact single and double ionization of helium

et al. 2004

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“…Furthermore, two pseudo-orbitals, 3s and 3p, were used to improve the description of the He(1s 2 ) ground state. This improvement was considered essential in light of the discrepancies between earlier predictions (Raeker et al 1994) and the absolute cross section data of Forand et al (1985) and Fuelling et al (1991) for ionization and simultaneous excitation of He(2p 2 P). Although the present results are closer to experiment and those predicted in the calculation of Rudge (1988), who used a variationally designed ground state but a plane-wave description for the ionizing electron, there is clearly a need for an improved theoretical model.…”

Section: Numerical Calculationsmentioning

confidence: 99%

A short biography of Mikhail Yakovlevich Suslin

Igoshin¹

1996

Russ. Math. Surv.

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We have measured the alignment A 20 ( 2 P) of He + (2p 2 P) after simultaneous ionization and excitation by electron impact via the non-isotropic angular distribution of photons of the decay He + (2p) → He + (1s) + γ (304Å). The range of incident electron energy E 0 was between E(He + , n = 2) = 65.4 eV and E(He + , n = 3) = 72.9 eV. Within experimental errors we obtained a constant value of A 20 ( 2 P) = −0.92(14) except in the range E 0 = 69-70.5 eV where the alignment has values between −1.2 and −1.3. These larger negative values can be explained by the decay of two-electron excitations 3 3 into He + (2p). The alignment value of −0.92 (14) indicates that in the investigated range of energy E 0 not only two-electron partial waves with L = 0 but also with L > 0 contribute to the ionization-excitation cross section. Our value of −0.92(14) agrees reasonably well with a nearly constant theoretical value of ≈ −0.67 obtained by a combined DWBA + R-matrix calculation.

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“…Integral moss sections of simultaneous ionization and excitation of He Woustafa Moussa and de Heer 1967, Bloemen et al 1981, Forrand et al 1985, Ne, Ar, and Kr atoms (Sanchez et al 1989(Sanchez et al , 1990) by elecwons were obtained experimentally. Theoretical calculations of the same process for He were also performed (Rudge 1988, Kuplyauskene and Maknitskas 1991).…”

Section: Introductionmentioning

confidence: 99%

Behaviour of Ionic Effects on Response Times of Surface Stabilized Ferroelectric Liquid Crystal Devices

Saxena¹,

Bawa²,

Biradar³

et al. 1990

Jpn. J. Appl. Phys.

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Photoionization cross sections for the 3p subshell electmns, wrrelation shake-up and conjugate shake.up satellite transitions in a relaxed-orbital Hamee-Fock framework within the dipole approximation a~ calculated. The potassium atom in lhe gmund and fust excited state 3p64p zP is considered. The single-configuration approach using pure LS and intermediate coupling of electron momenta is applied. The strong enhancement of the relative intensity of the shake-up correlation satellites in 3p inner-shell photoionization of the 3pb4p ' P excited state was obtained with respect to similar processes for the K atom in the ground state. ne LS J J J K LK ne LS J J JK LK ne LS J J J K LK 4s 0.88 0.68 0.68 0.68 4p 0.76 0.63 0.69~ 0.82 3d 0.85 0.62 o m 0.78 5s 052 0.96 0.96 0.96 5p 0.67 0.78 0.87 0.80 4d 0.75 069 0.69 0.75 6s 0.59 0.99 0.98 0.99 6p 0.63 0.85 0.95 0.77 5d 0.67 0.80 0.82 0.70

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Absolute electron impact emission cross section of the He⁺2²P to 1²S line at 304 AA produced by simultaneous ionisation-excitation

Cited by 55 publications

References 17 publications

Electron-impact single and double ionization of helium

Electron-impact single and double ionization of helium

A short biography of Mikhail Yakovlevich Suslin

Behaviour of Ionic Effects on Response Times of Surface Stabilized Ferroelectric Liquid Crystal Devices

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