Protonated acetylene in the z = 0.89 molecular absorber toward PKS 1830-211 S. Muller, R. Le Gal, E. Roueff, J. H. Black, A. Faure, M. Guélin, A. Omont, M. Gérin, F. Combes and S. Aalto A&A, 683 (2024) A62 Published online: 07 March 2024 DOI: 10.1051/0004-6361/202348994