Edwin E. Quashie edited Figure_ref_fig_stopping_power_shows__.tex  over 8 years ago

Commit id: 4b00388d17942ef84b093df43f7c365ee43fc984

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Figure \ref{fig:stopping_power} shows a comparison of our calculated electronic stopping power $S_\text{e}$ with \textsc{Srim} data.   In the channeling case, when the incident velocity $v$ increases after the maximum stopping is reached, the rate of decrease of our $S_\text{e}$ results becomes rather faster than those obtained by either the experimental or the SRIM database due to the following reasons: (i) the projectile moves in a rectilinear uniform movement through the center of the channel and produces a very weak interaction due to its short duration close to the target; (ii) only the effect of valence electrons of the target atoms in the pseudo potential model is considered, the inner electronic excitations which should enhance the $S_\text{e}$ in high energy have not been taken into account \cite{Quijada_2007} and (iii) at higher energies, where stopping gets maximum, the valence electrons become ionized and the contribution due to these plasma electrons to $S_e$ are significant. Similar effects were also reported earlier by Mao \emph{et al} for SiC by $\mathrm{H^+}$ and $\mathrm{He^{2+}}$ \cite{Mao_2015}, when the ion velocity exceeds certain value, a new mechanism, known as the plasma oscillation \cite{Bauer_1990} of the target electrons, for the electronic energy loss appears. Inclusion of these into our appears;  present TDDFT model is rather impossible now. describe it pretty well.  For the off-channeling case, there is a better agreement between the our $S_\text{e}$ results with the \textsc{Srim} data in most of the range.  Presumably in experiments where trajectories are not controlled, the projectile does indeed explore core regions of the host atoms.