Computation of Electron Impact Ionization Cross sections of Iron Hydrogen Clusters -- Relevance in Fusion Plasmas

Plasma-wall interaction (PWI) is one of the key issues in nuclear fusion research. In nuclear fusion devices, such as the JET tokamak or the ITER, first-wall materials will be directly exposed to plasma components. Erosion of first-wall materials is a consequence of the impact of hydrogen and its isotopes as main constituents of the hot plasma. Besides the formation of gas-phase atomic species in various charge states, di- and polyatomic molecular species are expected to be formed via PWI processes. These compounds may profoundly disturb the fusion plasma, may lead to unfavorable re-deposition of materials and composites in other areas of the vessel. Interaction between atoms, molecules as well transport of impurities are of interest for modelling of fusion plasma. $Q_{ion}$ by electron impact are such process also important in low temperature plasma processing, astrophysics etc. We reported electron impact $Q_{ion\thinspace }$for iron hydrogen clusters, FeH$_{\mathrm{n}}$ (n $=$ 1 to 10) from ionization threshold to 2000eV. A semi empirical approach called Complex Scattering Potential -- Ionization Contribution (CSP-\textit{ic}) has been employed for the reported calculation$^{\mathrm{1}}$. In context of fusion relevant species $Q_{ion}$ were reported for beryllium and its hydrides, tungsten and its oxides and cluster of beryllium-tungsten by Huber \textit{et al}$^{\mathrm{2}}$. Iron hydrogen clusters are another such species whose $Q_{ion}$ were calculated$^{\mathrm{2}}$ through DM and BEB formalisms, same has been compared with present calculations. $^{\mathrm{1}}$U. R. Patel \textit{et al}, J. Chem. Phys, \textbf{140} (2014) 44302 $^{\mathrm{2}}$S. E. Huber \textit{et al}, Eur. Phys. J. D. 70 (2016) 182