Low energy electrons can initiate and control chemical reactions through resonant attachment forming an electron-molecule compound state. Recently, it has been theoretically shown that free electrons can also act as catalysts in chemical reactions. We investigate this novel concept for the case of conversion of formic acid into CO. Resonant production of CO from cold formic acid films by low energy electron impact is observed using Fourier transform infrared spectroscopy. The resonant peak observed at 6 eV is identified as the catalytic electron channel. The experimental results are augmented with the quantum chemical calculations.

Radiation damage and stimulated desorption of nucleotides 2′-deoxyadenosine 5′-monophosphate (dAMP), adenosine 5′-monophosphate (rAMP), 2′-deoxycytidine 5′-monophosphate (dCMP), and cytidine 5′-monophosphate (rCMP) deposited on Au have been measured using x-rays as both the probe and source of low energy secondary electrons. The fluence dependent behavior of the O-1s, C-1s, and N-1s photoelectron transitions was analyzed to obtain phosphate, sugar, and nucleobase damage cross sections. Although x-ray induced reactions in nucleotides involve both direct ionization and excitation, the observed bonding changes were likely dominated by the inelastic energy-loss channels associated with secondary electron capture and transient negative ion decay. Growth of the integrated peak area for the O-1s component at 531.3 eV, corresponding to cleavage of the C—O—P phosphodiester bond, yielded effective damage cross sections of about 23 Mb and 32 Mb (1 Mb = 10−18 cm2) for AMP and CMP molecules, respectively. The cross sections for sugar damage, as determined from the decay of the C-1s component at 286.4 eV and the glycosidic carbon at 289.0 eV, were slightly lower (about 20 Mb) and statistically similar for the r- and d- forms of the nucleotides. The C-1s component at 287.6 eV, corresponding to carbons in the nucleobase ring, showed a small initial increase and then decayed slowly, yielding a low damage cross section (∼5 Mb). Although there is no statistical difference between the sugar forms, changing the nucleobase from adenine to cytidine has a slight effect on the damage cross section, possibly due to differing electron capture and transfer probabilities.

The Open University's repository of research publications and other research outputs Vacuum ultraviolet and infrared spectra of condensed methyl acetate on cold astrochemical dust analogs

The damage of approximately monolayer films of l-histidine by low-energy spin-polarized electrons (SPE) ejected from a magnetized cobalt substrate has been probed using X-ray photoelectron spectroscopy (XPS). Average damage cross sections for N-containing motifs of l-histidine are 25–30 and 2–5 Mb for zwitterions and neutral molecules, respectively. The magnetization direction of the substrate, which controls the ejected SPE helicity, was reversed in situ, and statistically significant differences in the damage cross sections of 10–30% were measured between positive and negative electron helicities. This is the first measurement of spin dichroism (SD) in an amino acid. The differential cross sections suggest that inelastic scattering of SPE with chiral molecules could contribute to the persistence of one enantiomer vs the other under certain irradiation conditions, particularly for the zwitterionic species.

Conversion of alkanes to functionalized compounds is a highly sought after goal. Under high reaction temperatures, desired intermediate products like alcohols, aldehydes, and carboxylic acids are more easily oxidized to CO 2 than the starting alkane, which makes it difficult to recover these functionalized compounds. Here, we use electrons with energy <20 eV to initiate reactions in pure methane and mixed layers of methane and oxygen condensed on a gold substrate at 15 K. Observation of ethane (in pure and mixed films) and methanol and formaldehyde (in mixed films) indicates methane activation by electrons. From the formation threshold and energy dependence of product yields, electronic excitation of reactant/s followed by dissociation into neutral radicals appears to be the reaction initiating step. The results demonstrate the utility of low energy electrons in bringing about functionalization in the simplest alkane.