Gas Phase Synthesis of Protonated Glycine by Chemical Dynamics Simulations

In the present work, we investigated the reaction dynamics that will possibly lead to the formation of protonated glycine by an ion-molecule collision. In particular, two analogous reactions were studied: NH₃OH⁺ + CH₃COOH and NH₂OH₂⁺ + CH₃COOH that were suggested by previous experiments to be able to form protonated glycine loosing a neutral water molecule. Chemical dynamics simulations show that both reactants can form a molecule with the mass of the protonated glycine but with different structures, if some translational energy is given to the system. The reaction mechanisms for the most relevant product isomers are discussed as well as the role of collision energy in determining reaction products. Finally, in comparing collision dynamics at room and at very low initial internal temperature of the reactants, the same behavior was obtained for forming the protonated glycine isomers products. This supports the use of standard gas phase ion-chemistry setups to study collision-induced reactivity as a model for astrophysical cold conditions, when some relative translation energy is given to the system.