Spectroscopic diagnostics of low-pressure inductively coupled Kr plasma using a collisional–radiative model with fully relativistic cross sections

Abstract

A collisional-radiative (C-R) model for krypton plasma using fully relativistic distortedwave cross sections for electron excitations was developed. The model was applied to the characterization of inductively coupled Kr plasma with cylindrical geometry over the pressure regime 1-50 mTorr. Radially averaged emission intensities from transitions of Kr (4p 5 5p → 4p 5 5s) in the range 500-900 nm were recorded at 17 cm from the planar RF-driven coil, with the plasma operated in the inductive regime (H mode). The measured emission intensities were then fitted by varying the electron density, n e , and electron temperature, T e , in the C-R model. At both low and high pressures, variations of the electron density by over two orders of magnitude had only a minor role on the relative emission intensities. On the other hand, T e values deduced from the comparison between experiment and model decreased from 6.7 to 2.6 eV as pressure increased from 1 to 50 mTorr. These results are found to be in good agreement with the effective electron temperature determined from Langmuir probe measurements and the predictions of a model based on the particle balance equation of charged particles.

LXCat: an Open‐Access, Web‐Based Platform for Data Needed for Modeling Low Temperature Plasmas

“…[93] For krypton, the cross sections have been published as follows: from the ground state to the 5 s manifold, [94] to the 4 d, 5 p, and 6 s manifolds [95] and to the 6 p manifold [96] ; from the 5 s metastable levels to the 5 s and 5 p manifolds [97] ; from the 5 s manifold to the 6 p manifold. [96] These cross sections have been incorporated into a collisional-radiative model for low temperature plasmas. [93,96] Similar data for other transitions can be provided upon request.…”

“…[96] These cross sections have been incorporated into a collisional-radiative model for low temperature plasmas. [93,96] Similar data for other transitions can be provided upon request.…”

“…For krypton, the cross sections have been published as follows: from the ground state to the 5 s manifold, to the 4 d, 5 p, and 6 s manifolds and to the 6 p manifold; from the 5 s metastable levels to the 5 s and 5 p manifolds; from the 5 s manifold to the 6 p manifold …”

Diagnostics of Ne–Ar mixture plasma using a fine‐structure resolved collisional radiative model

“…[24] In various modelling and diagnostic studies, these cross-sections were employed. [20,25] In the present work, the EIE cross-sections for neon from the ground state to the upper excited fine-structure levels and among the excited levels have been used in the model that was reported by us. [19] At low-pressure conditions, the electron energy distribution could deviate from the Maxwellian form.…”

Electron Impact Excitation of Extreme Ultra-Violet Transitions in Xe7–Xe10 Ions

“…It is clear from the above discussion that most of the previous experimental or theoretical studies on Xe 7+ -Xe 10+ ions have focused on their spectroscopic properties, while the electron impact cross section data are scarcely reported. However, various studies in the past have clearly demonstrated that using accurate cross section results in a collisional radiative model provides a better agreement with the measurements on the plasma parameters, viz., electron temperature and density [17][18][19][20]. Therefore, reliable cross sections are essential for the success of any plasma model.…”