Velocity dependence of the energy loss of very slow proton and deuteron beams in Cu and Ag

Electronic Stopping Power in Gold: The Role ofdElectrons and theH/HeAnomaly

“…Substantial progress has been made for weakly non-adiabatic problems such as the chemistry of vibrationally excited molecules landing on metal surfaces [1], but not in the stronger coupling regime of radiation damage. Recently, the electronic stopping power for swift ions in gold has been carefully characterized by experiments [2][3][4], showing flagrant discrepancies with the established paradigm for such problems [5,6], and only qualitative agreement with time-dependent tight-binding studies [7], and with detailed studies for protons based on first principles [8], leaving very fundamental questions unanswered in spite of the apparent simplicity of the system. Most notably the H/He anomaly: the present understanding predicts a stopping power for H higher than for He at low velocities [6], which strongly contradicts the recent experiments [4].…”

Experimental study and computer simulations of the energy loss straggling of slow ions in thin foils: Results for H+ and D+ in C, Si, Cu, Ag and Bi

“…(1) was verified for protons and deuterons in C and Al, down to very low energies [3,11], while in noble metals a departure from this dependence was observed [2,[6][7][8]. A physical explanation of this behavior was given considering the behavior of the nearly-free d electrons in those metals [2,6].…”

“…In fact, the main experimental difficulties at low energies arise from the greater influence of target roughness due to the requirement of using very thin targets, leading to disadvantageous roughness to thickness ratios. For this reason, although there are several accurate measurements of stopping powers down to very low energies ($1-2 keV) [2][3][4][5][6][7][8][9][10][11], there are very few experimental determinations of straggling values for energies below 10 keV [12]. Also, as shown by Konac et al [12], there are significant discrepancies in low-energy straggling data reported by different groups, which gradually disappear at larger energies.…”

Theoretical study of the channeling effect in the electronic stopping power of silicon carbide nanocrystal for low-energy protons and helium ions

“…A special attention is paid to the electronic stopping of light ions with low velocities in noble metals (Au, Ag and Cu). In noble metals, the measured SP of slow protons has shown unexpected deviations from the velocity proportionality, and a complex structure of the SP versus ion velocity is observed in the range of low energies [23][24][25].…”