Influence of pressure on the relative population of the two lowest vibrational levels of the C 3Πu state of nitrogen for electron beam excitationA. Morozov, T. Heindl, J. Wieser, R. Krücken and A. UlrichEur. Phys. J. D, 46 1 (2008) 51-57DOI: https://doi.org/10.1140/epjd/e2007-00278-2