Referenced in: none

Automatically associated channels: Slo1

Title: A Multicoincidence Study of Fragmentation Dynamics in Collision of γ-Aminobutyric Acid with Low-Energy Ions.

Authors: Michael Capron, Sergio Díaz-Tendero, Sylvain Maclot, Alicja Domaracka, Elie Lattouf, Arkadiusz Lawicki, Rémi Maisonny, Jean-Yves Chesnel, Alain Méry, Jean-Christophe Poully, Jimmy Rangama, Lamri Adoui, Fernando Martin, Manuel Alcamí, Patrick Rousseau, Bernd A Huber

Journal, date & volume: Chemistry, 2012 Jul 23 , 18, 9321-32

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22733693

Abstract
Fragmentation of the γ-aminobutyric acid molecule (GABA, NH(2)(CH(2))(3)COOH) following collisions with slow O(6+) ions (v≈0.3 a.u.) was studied in the gas phase by a combined experimental and theoretical approach. In the experiments, a multicoincidence detection method was used to deduce the charge state of the GABA molecule before fragmentation. This is essential to unambiguously unravel the different fragmentation pathways. It was found that the molecular cations resulting from the collisions hardly survive the interaction and that the main dissociation channels correspond to formation of NH(2)CH(2)(+), HCNH(+), CH(2)CH(2)(+), and COOH(+) fragments. State-of-the-art quantum chemistry calculations allow different fragmentation mechanisms to be proposed from analysis of the relevant minima and transition states on the computed potential-energy surface. For example, the weak contribution at [M-18](+), where M is the mass of the parent ion, can be interpreted as resulting from H(2)O loss that follows molecular folding of the long carbon chain of the amino acid.