M. Bertin

Reactivity induced at 25 K by low-energy electron irradiation of condensed NH3-CH3COOD (1:1 mixture!

Chemical reactivity is observed following electron irradiation of a binary mixture of ammonia (NH(3)) and acetic acid (CH(3)COOD) at 25 K, without any subsequent thermal activation, as evidenced by vibrational high resolution electron energy loss spectroscopy (HREELS). Analysis of the HREEL spectra and comparison with infrared and Raman data of different molecules are compatible with glycine formation in its zwitterionic form. The onset for electron induced reaction is found to be at about approximately 13 eV. The mechanisms may involve NH radicals interaction with CH(3)COOD molecules. Then glycine formation does not imply any displacement of reactants, so that it involves only NH(3) and CH(3)COOD neighboring molecules.

Vibrational study of hydrogen bonding to ion irradiated diamond surfaces

High resolution electron energy loss spectroscopy has been used to probe hydrogenated diamond film surfaces exposed to 1keV Ar+ ions at a dose of ∼1015cm−2 and thermal annealing. The defects induced on the upper atomic layers were identified with regard to the different hydrogenated species hybridization states as well as their thermal stability. Ion irradiation resulted in the coexistence of a partially hydrogenated disordered near surface region including CH species bonded in sp, sp2, and sp3 bonding configurations and CC dimers. Thermal annealing of the ion beam irradiated hydrogenated surface leads to complete hydrogen desorption at ∼650°C. This temperature is significantly lower compared to a well defined diamond surface for which an annealing temperature above 900°C is needed.

Amino Acid Formation by Electron Irradiation

The origin of amino acid formation in the early years is still not well known. Munoz Caro and collaborators showed the generation of amino acid by UV irradiation of a mixture of organic molecules reproducing the interstellar media. Although the photochemistry is one of the mechanism which would be active in the early years, it is also important to study other mechanisms such as the electrochemistry or electron induced chemistry which would act as well as a tool for the amino acid formation. The aim of this work is to demonstrate the amino acid formation by low energy electron irradiation of condensed organic molecules. In particular, our purpose is the formation of glycine by low energy electron irradiation of a film composed of a mixture of condensed NH3 and CH3COOD. Prior to the study of amino acid formation it is important to know about the effect of the interaction between electrons and organic molecules, so the first step in this work is the study of the electron irradiation of NH3 and CH3COOD films ...