Probably you should open a separate thread. I assume you needan ewald section as well. There is the section force_eval%MM%poisson%ewald . It has a GMAX keyword that oyu need to set. -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20150428/858dd799/attachment.htm>