Dear All, When reading the lecture notes about DFPT, I met following similar terms: "star of q", " q star", I was wondering what are they referred to. Do they mean "q*"? Thank you. Andy -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20120321/8f2ec076/attachment.html>