Cross sections for the two-step radiative decay process X(v)rightarrow A(v^{prime prime })rightarrow X(v^prime ) in e-LiH collisions

Roberto Celiberto,Annarita Laricchiuta

doi:10.1140/epjd/s10053-021-00164-x

Abstract

The cross sections for the two-step process, represented by the electron-impact vibro-electronic excitation X^1varSigma ^+(v) rightarrow A^1varSigma ^+(v'') of the LiH molecule, followed by radiative decay back on the vibrational manifold of the ground state, A^1varSigma ^+(v'')rightarrow X^1varSigma ^+(v'), are calculated as a function of the incident electron energy from the threshold to 1000 eV. The final cross sections for the two-step process, which results in an overall vibrational excitation of the molecule, known also as E-v process, are provided for all the possible v,v' transitions among the vibrational levels, including the continuum, of the electronic ground state.Graphic abstract

Highlights

One of the main problems arising in the realization of the thermonuclear fusion for civil consumption of energy is represented by the occurrence of intense release of power flux, generated by discharge disruption and edge-localized modes [1,2], which creates transient localized instabilities in the fusion plasma, leading to excessive thermal load on the plasma-facing components (PFC) of experimental reactors
Our calculations give results somewhat larger than those of Partridge and Langhoff. These authors, use their own potential curve for the ground state while we resorted to the more recent calculations by Tung et al [25], who performed a variational approach with explicitly correlated Gaussian functions (ECGs) including adiabatic corrections, obtaining a spectroscopically accurate estimation of vibrational levels and dissociation energy
No experimental or theoretical data are available for comparison, so we are confident that their accuracy reflects that of the electron– molecule cross sections and Einstein’s coefficients discussed in the previous section

Summary

Introduction

One of the main problems arising in the realization of the thermonuclear fusion for civil consumption of energy is represented by the occurrence of intense release of power flux, generated by discharge disruption and edge-localized modes [1,2], which creates transient localized instabilities in the fusion plasma, leading to excessive thermal load on the plasma-facing components (PFC) of experimental reactors In these conditions, the plasma–material interactions can cause serious damages to the internal device surface, resulting from the ablation, physical sputtering and chemical erosion of the wall materials. The typical mechanism that the vapour shielding is based on is originated by the conversion, through collisions, of the particle kinetic energy in internal excitation of the evaporated metallic species, followed, after relaxation, by radiation emission isotropically released in the plasma bulk, away from the walls In this framework, lithium-containing molecules (Li2, LiH) can play an important role.

Cross section calculation

Results

Conclusion