Excitation of the first electronic states, vibrational excitation between 1 and 3 eV, and negative ion formation (0-2 eV) in gas phase 5-nitrouracil are presented. Five singlet states are clearly identified at 4.76; 5.72; 6.82; 7.82 and 9.2 eV. A band at 3.7 eV could be assigned to a triplet state. The vibrational modes observed indicate resonant states having both pi* and sigma* character. The most intense anions (M-NO2) , (M-H) appear at zero energy with huge cross sections (>= 10 18 m(2)). Anion cross sections versus electron energy reveal structures interpreted using the anion energy thresholds found by DFT calculations. (C) 2008 Elsevier B.V. All rights reserved.