Time dependent diagnostics of laser ablated silicon plasma using fully relativistic electron excitation cross-section of Si⁺²

Laser ablated silicon plasma has significant application in pulse laser deposition, etching processes etc. [1,2]. In view of these, we have developed a time dependent collisional radiative (CR) model for the diagnostics of laser ablated Silicon plasma. In such plasmas, the electron and gas temperatures are low and electron impact excitation (EIE) and de-excitation processes are dominant. For a reliable CR model, the EIE cross-sections for a large number of transitions of Si⁺² are required [3] which we have calculated for the first time using Relativistic Distorted Wave (RDW) approach[4]. The transitions considered are from ground state 3s² (J = 0) to the fine structure levels of the 3s3p, 3p², 3s3d, 3s4s, 3s4p, 3s5s, 3s4d , 3s4f, 3s5p, 3s5d and 3s5f configurations as well as among the upper levels. We also include radiative decay, ionization, and recombination processes in the CR model. We have validated our model with the optical emission spectroscopic (OES) measurement of Wang et al.[5] on laser induced silicon plasma. The obtained plasma parameters viz. electron temperature, electron density etc. are compared with the corresponding experimental values. The details of our EIE cross-section calculations, full description of the CR model along with the obtained results will be presented in the conference.   

[1]      Schwan J  et al., 2022 J. Phys. D. Appl. Phys. 55 094002

[2]      Traversari S et al., 2021 Plant Physiol. Biochem. 166 1014

[3]      Boffard J B et al., 2018  Advances in Atomic, Molecular and Optical Physics  67 1

[4]      Baghel S S, Gupta S, Gangwar R K and Srivastava R 2019 Plasma Sources Sci. Technol. 28 115010

[5]      Wang K et al., 2020 Phys. Plasmas 27 063513