  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.
