Electron spectroscopy in proton collisions with dry gas-phase uracil base

Abstract

We have investigated the electron emission by the RNA uracil base $({\mathrm{C}}_{4}{\mathrm{H}}_{4}{\mathrm{N}}_{2}{\mathrm{O}}_{2})$ due to collisions with protons in the $25\phantom{\rule{0.3em}{0ex}}\mathrm{keV}--100\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$ energy range. Electron spectroscopy was performed at 35\ifmmode^\circ\else\textdegree\fi{} with respect to the beam direction and absolute values for the double-differential cross section were obtained. Our results show preferential emission of low-energy electrons that are responsible for damage in biological material through dissociative electron attachment [Bouda\"{\i}ffa et al., Science 287, 1658 (2000)]. Experimental results are compared to calculations that used the classical trajectory Monte Carlo method, and a reasonable agreement is obtained.