The Tian Pseudo-Atom Method

Abstract: In this work, the authors give a new method for phase determination, the Tian pseudo atom method (TPAM) or pseudo atom method (PAM) for short. In this new method, the figure of merit function, Rtian, replaces Rcf in the charge flipping algorithm. The key difference between Rcf and Rtian is the oberved structure factor was replaced by the pseudo structure factor. The test results show that Rtian is more powerful and robust than Rcf to estimate the correct structure especially with low resolution data. Therefore, the pseudo atom method could overcome the charge flipping method's defeat to some extent. In theory, the pseudo atom method could deal with quite low resolution data but it needs a further test.