In this Letter we present triple differential cross sections for equal energy sharing kinematics for double photoionization of the helium atom at 20 and 40 eV above threshold in the framework of the hyperspherical partial wave theory. This supplements our earlier work [J. Phys. B: At. Mol. Opt. Phys. 36 (2003) 2707] in which we were successful in showing fully, gauge independence of the results in our formalism. Also in this Letter we treat cases in which the Stokes parameter S1 &lt; 1 so that partial polarization of the photon source is also taken into account. Agreement in shape with the convergent close coupling [A.S. Kheifets, 2003, private communication; H. Bräuning, et al., J. Phys. B: At. Mol. Opt. Phys. 31 (1998) 5149] calculation and the experiments appears to be excellent. © 2003 Elsevier B.V. All rights reserved.

J N DAS

K CHAKRABUTI

S PAUL

Fulltext

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Physics Letters, Section A: General, Atomic and Solid State Physics

An ab initio calculation of triple differential cross-section for double photoionization of helium atoms are presented for a very low energy of just 1 eV above threshold in the equal energy sharing kinematics. We have used hyperspherical partial wave theory together with a Numerov difference scheme in place of other schemes used in our earlier works. The results are in excellent qualitative agreement with the measurements of Dörner et al. [Phys. Rev. A 57, 1074 (1998)].

European Physical Journal D

Double photoionization of helium atoms at 1 eV above threshold

The double photoionization of helium atoms in hyperspherical partial wave theory at 6 eV above threshold was investigated to obtain converged cross-section results for equal energy sharing geometries. The calculations were practically converged with 100 channels for the kinematical conditions considered. The 100-channel and 150-channel results were shown to be practically indistinguishable. The results show some undulation around -25°C.

Physical Review A - Atomic, Molecular, and Optical Physics

Converged cross-section results for double photoionization of helium atoms in hyperspherical partial wave theory at 6 eV above threshold

The calculation of the triple differential cross sections for the ionization of hydrogen atoms by electron impact at low energies for various equal-energy-sharing kinematic conditions was performed. The hyperspherical partial-wave theory was applied for the purpose. For different kinematic conditions at 17.6 eV, the agreement of the cross section results with the recent absolute measurements of and with the latest theoretical results of the ECS and CCC calculation was very appropriate.

Hyperspherical partial-wave theory applied to electron-hydrogen-atom ionization calculation for equal-energy-sharing kinematics

The hyperspherical partial wave approach has been applied here in the study of double photoionization of the helium atom for equal-energy-sharing geometries at 20 eV excess energy. Calculations have been done both in length and velocity gauges and are found to agree with each other, with the CCC results and with experiments and to exhibit some advantages for the corresponding three-particle wavefunction over other wavefunctions in use.

Journal of Physics B: Atomic, Molecular and Optical Physics

Hyperspherical partial wave calculation for double photoionization of the helium atom at 20 eV excess energy

The hyperspherical partial wave method (Das [7]) has been presented here in a symmetric form so that effects of coupling among different partial waves may be included in a systematic way. It is also outlined here how to solve the relevant coupled set of radial wave equations numerically. Some preliminary results are presented for S,P and D waves in the low energy domain of 30-50eV for the incident electron. In this calculation only two important partial waves are included in each channel. The results are compared with experimental ones and appear very encouraging.

Journal	Data powered by TypesetPhysics Letters, Section A: General, Atomic and Solid State Physics
Publisher	Data powered by TypesetElsevier
ISSN	0375-9601
Open Access	Yes