The 2Πg shape resonance of acetylene anion: an investigation with the RAC method Roman Čurík, Ivana Paidarová and Jiří Horáček Eur. Phys. J. D, 70 7 (2016) 146 Published online: 05 July 2016 DOI: 10.1140/epjd/e2016-70133-6