Production of intense beams of mass-selected water cluster ions and theoretical study of atom-water interactions

TL;DR

This paper combines experimental and theoretical approaches to study water molecule interactions with heavy particles, focusing on collision dynamics and producing mass-selected water cluster ions to understand radiation effects on biological molecules.

Contribution

It introduces a joint experimental-theoretical framework and reports the first size distributions of protonated water cluster ions using a new apparatus.

Findings

First size distributions of protonated water cluster ions (n=2-39) produced.

Application of TDDFT coupled with MD for collision studies.

Experimental data on projectile interactions with water clusters.

Abstract

The influences of water molecules surrounding biological molecules during irradiation with heavy particles (atoms,ions) are currently a major subject in radiation science on a molecular level. In order to elucidate the underlying complex reaction mechanisms we have initiated a joint experimental and theoretical investigation with the aim to make direct comparisons between experimental and theoretical results. As a first step, studies of collisions of a water molecule with a neutral projectile (C atom) at high velocities (> 0.1 a.u.), and with a charged projectile (proton) at low velocities (< 0.1 a.u.) have been studied within the microscopic framework. In particular, time-dependent density functional theory (TDDFT) was applied to the valence electrons and coupled non-adiabatically to Molecular dynamics (MD) for ionic cores. Complementary experimental developments have been carried out to study projectile interactions with accelerated (< 10 keV) and mass-selected cluster ions. The first size distributions of protonated water cluster ions H+(H_2O)_n (n=2-39) produced using this new apparatus are presented.