UV-driven chemistry in simulations of the interstellar medium - I. Post-processed chemistry with the Meudon PDR codeF. Levrier, F. Le Petit, P. Hennebelle, P. Lesaffre, M. Gerin and E. FalgaroneA&A, 544 (2012) A22DOI: https://doi.org/10.1051/0004-6361/201218865