Atoms

11 pages, 650 KiB

Open AccessArticle

Calculation of the Differential Breit-Rosenthal Effect in Pb

by Martin Kinden Karlsen and Jonas R. Persson

Atoms 2024, 12(1), 5; https://doi.org/10.3390/atoms12010005 - 16 Jan 2024

Viewed by 1301

Recent advancements in studying long chains of unstable nuclei have revitalised interest in investigating the hyperfine anomaly. Hyperfine anomaly is particularly relevant for determining nuclear magnetic dipole moments using hyperfine structures where it limits the accuracy. This research paper focuses on the calculation [...] Read more.

Recent advancements in studying long chains of unstable nuclei have revitalised interest in investigating the hyperfine anomaly. Hyperfine anomaly is particularly relevant for determining nuclear magnetic dipole moments using hyperfine structures where it limits the accuracy. This research paper focuses on the calculation of the differential Breit-Rosenthal effect for the

6 p^{2}^{3} P_{1, 2}

,

^{1} D_{2}

and

6 p 7 s^{3} P_{1}

states in Pb, utilising the multi-configurational Dirac-Hartree-Fock code, GRASP2018. The findings show that the differential Breit-Rosenthal effect is typically less than

0.1 / f m^{2}

, which is often much smaller than the Bohr-Weisskopf effect. The differential Breit-Rosenthal effect for the

6 p^{2}^{3} P_{2}

state is one order of magnitude smaller than the rest, which is why this state seems to be insensible to the hyperfine anomaly. Full article

► Show Figures

Figure 1

12 pages, 1539 KiB

Open AccessArticle

Energy Shift of the Atomic Emission Lines of He-like Ions Subject to Outside Dense Plasma

by Tu-Nan Chang, Te-Kuei Fang, Rui Sun, Chensheng Wu and Xiang Gao

Atoms 2024, 12(1), 4; https://doi.org/10.3390/atoms12010004 - 15 Jan 2024

Viewed by 1335

Abstract

We present an extension of our study of the energy shift of the atomic emissions subject to charged-neutral outside dense plasma following the good agreement between the experimental measurements and our recent theoretical estimates for the

α

and

β

emission lines of a [...] Read more.

We present an extension of our study of the energy shift of the atomic emissions subject to charged-neutral outside dense plasma following the good agreement between the experimental measurements and our recent theoretical estimates for the

α

and

β

emission lines of a number of H-like and He-like ions. In particular, we are able to further demonstrate that the plasma-induced transition energy shift could indeed be interpolated by the simple quasi-hydrogenic picture based on the application of the Debye–Hückel (DH) approximation for the

n = 3

to

n = 2

transitions of the He-like ions. Our theoretically estimated redshifts of those emissions may offer the impetus for additional experimental measurement to facilitate the diagnostic efforts in the determination of the temperature and density of the dense plasma. Full article

(This article belongs to the Special Issue Atomic Physics in Dense Plasmas)

► Show Figures

Figure 1

10 pages, 454 KiB

Open AccessArticle

Basis Set Calculations of Heavy Atoms

by Mikhail G. Kozlov, Yuriy A. Demidov, Mikhail Y. Kaygorodov and Elizaveta V. Tryapitsyna

Atoms 2024, 12(1), 3; https://doi.org/10.3390/atoms12010003 - 12 Jan 2024

Viewed by 1359

Abstract

Most modern calculations of many-electron atoms use basis sets of atomic orbitals. An accurate account for electronic correlations in heavy atoms is a very difficult computational problem, and an optimization of the basis sets can reduce computational costs and increase final accuracy. Here, [...] Read more.

Most modern calculations of many-electron atoms use basis sets of atomic orbitals. An accurate account for electronic correlations in heavy atoms is a very difficult computational problem, and an optimization of the basis sets can reduce computational costs and increase final accuracy. Here, we propose a simple differential ansatz to form virtual orbitals from the Dirac–Fock orbitals of the core and valence electrons. We use basis sets with such orbitals to calculate different properties in Cs including hyperfine structure constants and QED corrections to the valence energies and to the

E 1

transition amplitudes. Full article

► Show Figures

Figure 1

12 pages, 655 KiB

Open AccessArticle

R-Matrix Calculation of Electron Collision with the BeO⁺ Molecular Ion

by Nilanjan Mukherjee, Abhijit Bhattacharyya and Kalyan Chakrabarti

Atoms 2024, 12(1), 2; https://doi.org/10.3390/atoms12010002 - 10 Jan 2024

Viewed by 1408

Abstract

We report here an R-matrix study of electron collision with the BeO

^{+}

molecular ion in its X

^{2} Π

ground state and at a single bond length, namely its equilibrium

R_{e} = 2.7023

a_{0}

. Firstly, a good [...] Read more.

We report here an R-matrix study of electron collision with the BeO

^{+}

molecular ion in its X

^{2} Π

ground state and at a single bond length, namely its equilibrium

R_{e} = 2.7023

a_{0}

. Firstly, a good quality configuration interaction calculation is performed for the BeO

^{+}

ground and excited states. We then perform scattering calculations using the R-matrix method to yield the cross-section for electronic excitation to several of its excited states. The electron impact dissociation of BeO

^{+}

through the two lowest dissociation channels, namely the Be

^{+} (^{2} S_{g})

+ O

(^{3} P_{g})

and Be

^{+} (^{2} S_{g})

+ O

(^{1} D_{g})

dissociation channels, is estimated using the electronic excitation cross-sections. Rotational excitation cross-sections are provided for the

j (= 0) \to j^{'} (= 1, 2, 3)

rotational transitions. Our calculations also yield e + BeO

^{+}

neutral Feshbach resonances and their widths which we present systematically categorized by their symmetry and quantum defects, and BeO-bound Rydberg states at the BeO

^{+}

equilibrium. The full potential energy curves for the resonant states, their widths and the bound Rydberg states, whose details we propose to give in a subsequent work, can be the starting point of other collision calculations. Full article

(This article belongs to the Special Issue Calculations and Measurements of Atomic and Molecular Collisions)

► Show Figures

Figure 1

15 pages, 2180 KiB

Open AccessArticle

Better Understanding of Hydrogen Pellet Ablation Cloud Spectra through the Occupation Probability Formalism in LHD

by Motoshi Goto, Gen Motojima, Ryuichi Sakamoto, Bernard Pégourié, Akinobu Matsuyama, Tetsutarou Oishi, Tomoko Kawate and Yasuko Kawamoto

Atoms 2024, 12(1), 1; https://doi.org/10.3390/atoms12010001 - 8 Jan 2024

Viewed by 1317

Abstract

We have recently incorporated the occupation probability formalism (OPF) in the simulation model [C. Stehlé and S. Jacquemot, Astron. Astrophys. 271, 348 (1993)] to have a smooth transition from discrete lines to continuum spectrum in the wavelength range near the Balmer [...] Read more.

We have recently incorporated the occupation probability formalism (OPF) in the simulation model [C. Stehlé and S. Jacquemot, Astron. Astrophys. 271, 348 (1993)] to have a smooth transition from discrete lines to continuum spectrum in the wavelength range near the Balmer series limit. We have analyzed spectra measured for the hydrogen pellet ablation cloud in the Large Helical Device with the revised model, and have found that the electron density in the ablation cloud has a close correlation with the electron temperature of the background plasma. This type of correlation is first confirmed in the present analysis and should give a new insight in the simulation studies of pellet ablation for the magnetically confined fusion plasma. Full article

(This article belongs to the Section Atomic, Molecular and Nuclear Spectroscopy and Collisions)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Atoms, Volume 12, Issue 1 (January 2024) – 5 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI