Issue 33, 2022

Velocity correlated emission of secondary clusters by a single surface impact of a polyatomic ion: a new mechanism of cluster emission and subpicosecond probing of extreme spike conditions

Abstract

Emission of secondary clusters off clean solid surfaces following the impact of a projectile ion at kiloelectronvolt (keV) kinetic energies is important from both practical and fundamental points of view. Understanding the underlying emission mechanisms using different types and sizes of projectile ions is therefore of high interest. In this perspective article we provide an up-to-date review of our recently observed new mechanism of velocity correlated cluster emission (VCCE) describing the emission of large clusters off different targets following the impact of a large polyatomic ion (C60). Due to its large collision cross section and large number of light constituent atoms, the incoming C60 disintegrates completely upon an impact resulting in a rather broad and shallow energy deposition, high subsurface energy density and ultrafast evolution of an extreme nonlinear collision cascade dynamics. It is shown that kinetic energy distributions (KEDs) of the emitted clusters behave very differently from the KEDs of cluster ions emitted following the impact of a heavy monoatomic ion. All the large clusters emitted from a given target (following the keV C60 impact) move with nearly the same velocity and their KEDs could be fairly well described by a shifted Maxwellian. Namely, a thermal distribution superimposed on a center-of-mass velocity of a moving precursor which is the source of the emitted clusters. So far we have measured and analyzed KEDs for NbnCn+, TanCn+,Agn+, Cun+, Aun+ and Aln+ clusters emitted from their respective metallic targets, thus demonstrating the general validity of the VCCE effect as a new sputtering mechanism. We have also proposed a simple model for the initial, subpicosecond emission step of the precursor (and the resulting emitted clusters) and supported it by molecular dynamics (MD) simulations of the thermal behavior of the impact induced spike on the subpicosecond timescale. It is shown that each complete family of measured cluster KEDs (for a given target) can serve as a unique diagnostic tool, probing the extreme temperature and pressure evolving in the impact induced spike. We will discuss our accumulated findings from new perspectives and report new observations and additional analysis aspects.

Graphical abstract: Velocity correlated emission of secondary clusters by a single surface impact of a polyatomic ion: a new mechanism of cluster emission and subpicosecond probing of extreme spike conditions

Article information

Article type
Perspective
Submitted
10 jan 2022
Accepted
13 jún 2022
First published
18 jún 2022

Phys. Chem. Chem. Phys., 2022,24, 19634-19658

Velocity correlated emission of secondary clusters by a single surface impact of a polyatomic ion: a new mechanism of cluster emission and subpicosecond probing of extreme spike conditions

E. Armon, A. Bekkerman, V. Bernstein, B. Tsipinyuk and E. Kolodney, Phys. Chem. Chem. Phys., 2022, 24, 19634 DOI: 10.1039/D2CP00145D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements