Fully relativistic electron-impact ionization of atomic ions

Abstract. An accurate knowledge of atomic collision processes is important for a better understanding of many astrophysical and laboratory plasmas. Collision databases which contain electron-impact excitation, ionization, and recombination cross sections and temperature dependent rate coefficients have been constructed using perturbative distorted-wave methods and non-perturbative R-matrix pseudo-states and time-dependent close-coupling methods. We present recent atomic collision results. IntroductionAccurate atomic and molecular databases underpin current research efforts in a variety of scientific and engineering areas: including controlled fusion energy, astrophysics, radiation biophysics, fluorescent lamps, and atmospheric pollutant removal. For example, all light elements (H-O) are of interest for fusion experiments; in particular Li and B as wall coating materials and Be and C as primary wall materials.Over the years both theory and experiment have provided increasingly more accurate cross sections for the electron-impact excitation, ionization, and recombination of atoms and their ions. In this paper we review perturbative distorted-wave methods and non-perturbative R-matrix with pseudo-states and time-dependent close-coupling methods in both their non-relativistic and fully-relativistic versions.The rest of the review paper is structured as follows: in Section II we describe distorted-wave, R-matrix, and time-dependent close-coupling methods and give an electron-impact ionization cross section example, and in Section III we give a brief review of current projects.

show abstract

“…Fully-relativistic subconfiguration-average distorted-wave ionization and excitation cross sections may also be calculated [2].…”

Section: Configuration-average Distorted-wave (Cadw) Methodsmentioning

confidence: 99%

Atomic Collision Processes for Astrophysical and Laboratory Plasmas

Pindzola

Loch

Ballance

et al. 2014

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…In this method, the fully-relativistic energies and bound-radial orbitals are generated using Grant's atomic structure code (Grant 2007). The details of this method can be found in Pindzola et al (1988) where it was used to calculate the electron-impact ionization of U 89+ and in Pindzola et al (1989) for the ionization plus excitation-autoionization of U 16+ .…”

Section: Distorted-wavementioning

confidence: 99%

Electron-impact excitation of H-like Cr, Mn, Fe, Co, and Ni for applications in modeling X-ray astrophysical sources

Malespin

Ballance

Pindzola

et al. 2011

A&A

Self Cite

View full text Add to dashboard Cite

Context. Accurate atomic data for the less abundance Fe-peak elements are required for use in X-ray astrophysical studies. Aims. We calculate high quality electron-impact excitation collision strengths and effective collision strengths for hydrogenic Cr, Mn, Fe, Co, and Ni. Methods. We use the Dirac R-matrix method, the intermediate coupling frame transformation R-matrix method, the semi-relativistic distorted-wave method and the fully-relativistic distorted-wave method to calculate collision strengths for each of the ions. The ADAS collisional-radiative codes are used to produce photon emissivity coefficients for each ion. Results. Results are presented for atomic energy levels, spontaneous emission coefficients, electron-impact excitation collision strengths and associated effective collision strengths for each of the five species under consideration. We find relativistic effects can contribute an approximate 10% increase to the background cross section in relation to semi-relativistic collision calculations. We also confirm that radiation damping plays a prominent role for certain near threshold resonances. In order check the integration of our results within collisional-radiative modeling codes, we have used the ADAS package for some preliminary modeling of photon emissivities. The atomic data shall be made available online through the OPEN-ADAS site and the CFADC database

show abstract

“…It should be emphasized that the mean configurations are used solely in determining the potentials to be used in calculating the radial functions with Eqs. (3) and (4) or the analogs for free electrons, and that basically the calculations are multiconfiguration calculations. Usually we include all the mixing among the states in a complex.…”

Section: Illustrative Results and Discussionmentioning

confidence: 99%

“…These are that (i) different potentials were used in calculating the radial functions with Eqs. (3) and (4) and their analogs for free electrons in the two sets of calculations, and (ii) the Breit interaction was included in calculating the scattering matrix elements in the MP calculations, while it was not in the present calculations. As found in Refs.…”

Section: Illustrative Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Rapid-ionization approach based on the factorization method

Sampson

Zhang

1992

Phys. Rev. A

View full text Add to dashboard Cite

The factorization method of Bar-Shalom, Klapisch, and Oreg [Phys. Rev. A 38, 1773 (1988)] is extended to relativistic-distorted-wave cross sections for ionization by electron impact. This leads to a very great simplification for complex ions. In particular, when mixing is confined to the states in a complex (having the same set of n values, parity, and J value), the ionization cross section takes the form of a summation over states of the product of a readily calculated quantity that depends only on target-ion properties, such as mixing coe%cients and angular momenta, and a cross section having exactly the same form as a hydrogenic cross section except that the radial functions should be calculated using the appropriate potential for the ion being considered. Similar results are obtained for intermediate coupling using LS-coupling notation and for totally nonrelativistic calcu1ations. On1y slightly more complicated formulas apply when mixing is included outside a complex. It is also noted that similar expressions apply for photoionization. Sample numerical results are obtained and compared with relativistic calculations of Moores and Pindzola [Phys. Rev. A 42, 5384 (1990)]. Quite good agreement is obtained when mixing is included among the same set of states.PACS number{s): 34.80.Kw

show abstract

Fully relativistic electron-impact ionization of atomic ions

Cited by 29 publications

References 13 publications

Atomic Collision Processes for Astrophysical and Laboratory Plasmas

Atomic Collision Processes for Astrophysical and Laboratory Plasmas

Electron-impact excitation of H-like Cr, Mn, Fe, Co, and Ni for applications in modeling X-ray astrophysical sources

Rapid-ionization approach based on the factorization method

Contact Info

Product

Resources

About