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

We have investigated the electron emission by the RNA uracil base (C₄H₄N₂O₂) due to collisions with protons in the 250.3em0exkeV--1000.3em0exkeV energy range. Electron spectroscopy was performed at 35^∘{} 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\"{}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.