Origin of CH in diffuse molecular clouds - Warm H and ion-neutral drift Valeska Valdivia, Benjamin Godard, Patrick Hennebelle, Maryvonne Gerin, Pierre Lesaffre and Jacques Le Bourlot A&A, 600 (2017) A114 Published online: 12 April 2017 DOI: 10.1051/0004-6361/201629905