On relativistic shifts of negative-ion resonances

Thylwe, Karl‐Erik

doi:10.1140/epjd/e2011-20530-4

Cited by 29 publications

(43 citation statements)

References 19 publications

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“…In the Regge pole methods the important and revealing energy-dependent Reggie trajectories are calculated. Their effective use in low-energy electron scattering has been demonstrated in for example (Felfli, Msezane, & Sokolovski, 2009;Thylwe, 2012). Indeed, our Regge pole methodology provides a novel and robust theoretical approach to the seemingly impossible task of determining definitively stable ground and metastable negative ion formation in low-energy electron collisions with complex heavy atoms such as the actinide atoms.…”

Section: Methods Of Calculationmentioning

confidence: 99%

“…Im λ n (E) versus Re λ n (E) (λ n (E) is the CAM) that probe electron attachment at the fundamental level near threshold, thereby allow the determination of reliable EAs. Thylwe (2012), investigated Regge trajectories, using the ABF potential, and demonstrated that for Xe atom the Dirac Relativistic and non-Relativistic Regge trajectories yielded essentially the same Re λ n (E) when the Im λ n (E) was still very small. This clearly demonstrates the insignificant difference between the Relativistic and non-Relativistic calculations at near threshold electron impact energies, if the appropriate physics is accounted for adequately as in this case.…”

Section: Methods Of Calculationmentioning

confidence: 99%

“…Here a remark is appropriate regarding the importance of relativistic effects in the calculations using the Regge pole methodology of low-energy electron scattering TCSs for the complex heavy atoms, leading to stable negative ion formation. One of the most important investigations concerning the role of relativity in low-energy electron scattering from complex heavy atoms using the ABF potential was carried out by Thylwe (2012). For atomic Xe the Dirac Relativistic and non-Relativistic Regge trajectories were contrasted near threshold and found to yield essentially the same Re λ(E) when the Im λ(E) was still very small, see Figure 2 of (Thylwe, 2012).…”

Section: Comparison Between Our Anionic Bes and Existing Theoretical mentioning

confidence: 99%

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Negative Ion Formation in Low-Energy Electron Collisions with the Actinide Atoms Th, Pa, U, Np and Pu

Felfli¹,

Msezane²

2019

APR

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Here we investigate ground and metastable negative ion formation in low-energy electron collisions with the actinide atoms Th, Pa, U, Np and Pu through the elastic total cross sections (TCSs) calculations. For these atoms, the presence of two or more open d-and f-subshell electrons presents a formidable computational task for conventional theoretical methods, making it difficult to interpret the calculated results. Our robust Regge pole methodology which embeds the crucial electron correlations and the vital core-polarization interaction is used for the calculations. These are the major physical effects mostly responsible for stable negative ion formation in low-energy electron scattering from complex heavy systems. We find that the TCSs are characterized generally by Ramsauer-Townsend minima, shape resonances and dramatically sharp resonances manifesting ground and metastable negative ion formation during the collisions. The extracted from the ground states TCSs anionic binding energies (BEs) are found to be 3.09eV, 2.98eV, 3.03eV, 3.06eV and 3.25eV for Th, Pa, U, Np and Pu, respectively. Interestingly, an additional polarization-induced metastable TCS with anionic BE value of 1.22eV is generated in Pu due to the size effect. We also found that our excited states anionic BEs for several of these atoms compare well with the existing theoretical electron affinities including those calculated using the relativistic configuration-interaction method. We conclude that the existing theoretical calculations tend to identify incorrectly the BEs of the resultant excited anionic states with the electron affinities of the investigated actinide atoms; this demonstrates the great need for experimental verification and unambiguous determination of their electron affinities.

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Section: Methods Of Calculationmentioning

confidence: 99%

Section: Methods Of Calculationmentioning

confidence: 99%

Section: Comparison Between Our Anionic Bes and Existing Theoretical mentioning

confidence: 99%

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Negative Ion Formation in Low-Energy Electron Collisions with the Actinide Atoms Th, Pa, U, Np and Pu

Felfli¹,

Msezane²

2019

APR

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“…Im λ n (E) versus Re λ n (E)(λ n (E) is the CAM) that probe electron attachment at the fundamental level near threshold, thereby allow the determination of reliable EAs. Thylwe [42], investigated Regge trajectories, using the ABF potential, and demonstrated that for Xe the Dirac Relativistic and non-Relativistic Regge trajectories yielded essentially the same Re λ n (E) when the Im λ n (E) was still very small. This clearly demonstrates the insignificant difference between the Relativistic and non-Relativistic calculations at near threshold electron impact energies, if the appropriate physics is accounted for adequately as in this case.…”

Section: Methods Of Calculationmentioning

confidence: 99%

Negative Ion Binding Energies in Complex Heavy Systems

Msezane

2018

Jour. Atomic Mole. Conden. Nano Phys.

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We review briefly the recent progress in the determination of accurate and reliable electron affinities (EAs) of complex heavy systems with the view of assessing the reliability of the existing measured and/or calculated EAs of these systems. We demonstrate using slow electron collisions with complex heavy systems a novel and robust approach to the determination of reliable EAs from negative ion formation. From the Regge-pole calculated elastic total cross sections (TCSs), characterized by Ramsauer-Townsend (R-T) minima, shape resonances and dramatically sharp resonances manifesting anionic formation, we extract the anionic binding energies (BEs) for the ground, metastable and excited anionic states formed during the collisions. The ground state anionic BEs located at the absolute values of the R-T minima are identified with the systems' EAs. Results for various complex heavy systems, including fullerene molecules are compared with available measurements and calculations.

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“…These relativistic effects exist for a single Dirac mass in a potential model, described by Dirac Theory [8][9][10]. In the present study, we ignored the spin context and focus on the effects of twobody mass index on the scattering phase shift of the Varshni potential model.…”

Section: Introductionmentioning

confidence: 99%