Microscopic simulation of methanol and formaldehyde ice formation in cold dense cores H. M. Cuppen, E. F. van Dishoeck, E. Herbst and A. G. G. M. Tielens A&A, 508 1 (2009) 275-287 Published online: 21 October 2009 DOI: 10.1051/0004-6361/200913119