Interplay between the Coulomb explosion and vicinage effects studied usingH2+molecules under channeling conditions

Abstract

The aim of this work is to investigate how the mean energy loss and straggling due to H 2 + molecules interacting with silicon are affected by the Coulomb explosion and vicinage effects. To that end, a SIMOX-type sample made up of 18 O and with an appropriate 18 O marker grown over the surface of crystalline Si was employed, allowing to carry out the measurements through the 18 O͑p , ␣͒ 15 N resonant reaction at 151.2 keV under channeling and random directions. The results show that the mean energy loss associated with the Coulomb explosion and vicinage effects are similar and amount each to about 2% of the total mean energy loss. The comparison of the energy straggling obtained for molecular beams at random and the well-aligned ͗100͘ direction shows a larger value for the aligned case, which is interpreted as a result of the Coulomb explosion along the channel direction. The experimental results are also discussed in terms of Monte Carlo simulations.

Role of electronic excitations in the energy loss ofH2+projectiles in high-κmaterials

“…The Coulomb explosion 11 tends to increase r 0 and the width of the energy loss distribution, the latter having little impact on the mean energy loss in amorphous media. 12,13 That makes its contribution to the energy loss ratio R n relatively small. On the other hand, the interference effect arising from the superposition of wake potentials is dependent on the internuclear distances of the fragments and can contribute directly to the energy loss of the fragments.…”

Coulomb Heating Behaviour of Fast Light Diclusters in Si<100> Direction

“…9 indicate that two third of the Coulomb explosion energy produces the Coulomb heating. The remaining one-third gives place to the longitudinal explosion of the molecules and therefore do not contribute to the Coulomb heating, contributing to the beam straggling instead (Fadanelli et al, 2006 + , B 2 + and C 2 + projectiles as a function of the estimated DHFS screened potential energy between the projectile components. All data seems to lay in a single straight line, with a slope about 0.6.…”

Vicinage effect in the energy loss of H2 dimers: Experiment and calculations based on time-dependent density-functional theory

“…In other words, there is an interference among the interactions of the different cluster components with the electrons of the target [8], which is often called the vicinage effect [9][10][11][12][13][14][15][16]. From an experimental point of view, the vicinage effect is usually quantified by measuring a stopping power ratio, i.e., the ratio between the stopping power of the cluster or molecule and the sum of the stopping powers of its constituents [17][18][19][20].…”