Unusual hydrogen and hydroxyl migration in the fragmentation of excited doubly-positively-charged amino acids in the gas phase

Sergio Díaz-Tendero,Rudy Delaunay,Fernando Martín,Bernd A Huber,Dariusz G Piekarski,Manuel Alcamí,Alicja Domaracka,Sylvain Maclot,Lamri Adoui,Patrick Rousseau

doi:10.1088/1742-6596/635/3/032037

Abstract

SynopsisWe present a combined experimental and theoretical study of the fragmentation of doubly-positively- charged amino acids in the gas phase. The combination of ab initio molecular dynamics simulations with ion- molecule collisions followed by multiple-coincidence mass spectrometric techniques, allows us to obtain a complete picture of the fragmentation dynamics. In addition to the expected Coulomb explosion, we have found evidence of hydrogen and hydroxyl-group migration processes, which leads to unusual fragmentation products.

Highlights

In this communication we present recent results on fragmentation of small lineal amino acids, doubly-positively charged in the gas phase, NH2−(CH2)n−COOH: n=1 glycine [10]; n=2 β−alanine [11] and n=3 γ−aminobutyric acid GABA [12]
In biological tissues the damages produced in the biomolecules are caused directly by the particle-matter collision and by radicals and secondary particles created after the fragmentation of different chemical species along the ionisation path [8,9]
This underlines the importance of a proper description of the fragmentation mechanisms after electron removal

Summary

Introduction

In this communication we present recent results on fragmentation of small lineal amino acids, doubly-positively charged in the gas phase, NH2−(CH2)n−COOH: n=1 glycine [10]; n=2 β−alanine [11] and n=3 γ−aminobutyric acid GABA [12]. Hadron therapy is radiation therapy using strongly interacting particles [1]. A better depth dose profile of the energetic ion beam (Bragg peak) has proven its superiority over gamma radiation for killing cancer cells selectively [2].

Results

Conclusion