Collision-energy-resolved Penning ionization electron spectroscopy of styrene, 2-vinylpyridine, and 4-vinylpyridine with He*(23S) metastable atomsM. Yamazaki, N. Kishimoto and K. OhnoEur. Phys. J. D, 38 1 (2006) 47-57DOI: https://doi.org/10.1140/epjd/e2005-00324-1