An optimum PML for scattering problems in the time domain Axel Modave, Abelin Kameni, Jonathan Lambrechts, Eric Delhez, Lionel Pichon and Christophe Geuzaine Eur. Phys. J. Appl. Phys., 64 2 (2013) 24502 Published online: 06 November 2013 DOI: 10.1051/epjap/2013120447