Dear Justin,Tsjerkand and Ravi, thanks from all of you for your kindness, I hop that I could use your recommend. anahita johari -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20110401/9c1a749f/attachment.html>