# The Tian Pseudo-Atom Method

## TL;DR

The Tian pseudo-atom method (TPAM) introduces a new phase determination approach that replaces the observed structure factor with a pseudo structure factor, showing improved robustness especially with low-resolution data.

## Contribution

This paper presents the Tian pseudo-atom method, a novel phase determination technique that enhances robustness over traditional charge flipping algorithms by using pseudo structure factors.

## Key findings

- Rtian outperforms Rcf in low-resolution data scenarios
- TPAM is more powerful and robust than traditional methods
- Potential to handle very low-resolution data

## 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.

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Source: https://tomesphere.com/paper/1702.01301