Stopping power of fluorides for low-velocity protons

Serkovic, L. N.; Sánchez, Esteban; Grizzi, O.; Eckardt, J. C.; Lantschner, G. H.; Arista, N. R.

doi:10.1103/physreva.76.040901

Cited by 24 publications

(20 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Very recent experiments demonstrated that below a certain velocity threshold no energy can be transferred to the electronic system of such an insulator. This occurs, however, at much lower ion velocity than expected [21][22][23]. Theoretical approaches by time-dependent density functional theory (DFT) are about to explain qualitatively the origin of the observed effect [24].…”

mentioning

confidence: 92%

Electronic Excitations of Slow Ions in a Free Electron Gas Metal: Evidence for Charge Exchange Effects

et al. 2011

View full text Add to dashboard Cite

Electronic energy loss of light ions transmitted through nanometer films of Al has been studied at very low ion velocities. For hydrogen, the electronic stopping power S is found to be perfectly proportional to velocity, as expected for a free electron gas. For He, the same is anticipated, but S shows a transition between two distinct regimes, in both of which S is velocity proportional-however, with remarkably different slopes. This finding can be explained as a consequence of charge exchange in close encounters between He and Al atoms, which represents an additional energy loss channel.

show abstract

mentioning

confidence: 92%

Electronic Excitations of Slow Ions in a Free Electron Gas Metal: Evidence for Charge Exchange Effects

et al. 2011

View full text Add to dashboard Cite

show abstract

“…More recently, an unambiguous velocity threshold at about 0.1 a.u. was measured for protons transmitted through AlF 3 thin films evaporated on self-supported C foils [9] and for proton, deuteron, and helium ions backscattered from LiF and KCl thin films [10].…”

Section: Introductionmentioning

confidence: 99%

“…), and a stopping power value which is half of the experimental one. In a previous work [9], we presented another model based on quantum scattering theory that takes into account the velocity distribution and the excitation of the active 2p electrons in the F − anions, and the properties of the electronic bands of the insulators. This model described the general trends and the measured velocity threshold of 0.1 a.u.…”

Section: Introductionmentioning

confidence: 99%

“…The behavior of the experimental stopping powers as a function of proton velocity is discussed and compared with the predictions of our theoretical model [9] based on calculations of the momentum transfer cross sections for the electron-ion collisions using quantum scattering methods, which incorporates the energy gap of the insulators and the organic semiconductor materials, and the velocity distributions of their corresponding active electrons. We also compared the experimental stopping powers with a model for compounds that includes Bragg additivity's rule [13] and the core and bond approach [14].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stopping power of fluorides and semiconductor organic films for low-velocity protons

et al. 2010

Self Cite

View full text Add to dashboard Cite

A combined experimental and theoretical study of the energy loss of protons in fluorides and organic films is presented. The measurements were performed in fresh AlF 3 , LiF, and N ,N -bis(1-ethylpropyl)-perylene-3,4,9,10tetracarboxdiimide (EP-PTCDI) evaporated in situ on self-supported C or Ag foils, covering the very low energy range from 25 keV down to 0.7 keV. The transmission method is used in combination with time-of-flight (TOF) spectrometry. In the case of fluorides with large band gap energies (AlF 3 and LiF), the experimental stopping power increases almost linearly with the mean projectile velocity showing a velocity threshold at about 0.1 a.u. These features are well reproduced by a model based on quantum scattering theory that takes into account the velocity distribution and the excitation of the active 2p electrons in the F − anions, and the properties of the electronic bands of the insulators. In the case of the semiconductor organic film with a lower gap, the experimental stopping power increases linearly with the mean projectile velocity without presenting a clear threshold. This trend is also reproduced by the proposed model.

show abstract

“…in LiF under grazing incidence [24]. Recent theoretical and experimental research managed to measure velocities in extremely low velocity regime (v ≤ 0.1 a.u) displaying a clear velocity threshold [20,[25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Ab initioelectronic stopping power and threshold effect of channeled slow light ions inHfO2

Wang

Liao

et al. 2017

Phys. Rev. B

View full text Add to dashboard Cite

We present ab initio study of the electronic stopping power of protons and helium ions in an insulating material, HfO2. The calculations are carried out in channeling conditions with different impact parameters by employing Ehrenfest dynamics and real-time, time-dependent density functional theory. The satisfactory comparison with available experiments demonstrates that this approach provides an accurate description of electronic stopping power. The velocity-proportional stopping power is predicted for protons and helium ions in the low energy region, which conforms the linear response theory. Due to the existence of wide band gap, a threshold effect in extremely low velocity regime below excitation is expected. For protons, the threshold velocity is observable, while it does not appear in helium ions case. This indicates the existence of extra energy loss channels beyond the electron-hole pair excitation when helium ions are moving through the crystal. To analyze it, we checked the charge state of the moving projectiles and an explicit charge exchange behavior between the ions and host atoms is found. The missing threshold effect for helium ions is attributed to the charge transfer, which also contributes to energy loss of the ion.

show abstract

Stopping power of fluorides for low-velocity protons

Cited by 24 publications

References 21 publications

Electronic Excitations of Slow Ions in a Free Electron Gas Metal: Evidence for Charge Exchange Effects

Electronic Excitations of Slow Ions in a Free Electron Gas Metal: Evidence for Charge Exchange Effects

Stopping power of fluorides and semiconductor organic films for low-velocity protons

Ab initioelectronic stopping power and threshold effect of channeled slow light ions inHfO2

Contact Info

Product

Resources

About