Hi,

In my system there are two sets, A and B. And I have two trajectory files of the system.

1. Move atoms of set A along the Z axis 0.1Å, then constrained A and run dynamics. The trajectory file 1.xtd;

2. Move atoms of set A along the Z axis 0.2Å, then constrained A and run dynamics. The trajectory file 2.xtd;

I append the two trajectory files.

Then I found in the new trajectory file, atoms of set A from 1.xtd changed their positions as same as that from 2.xtd.

I want to know why the position changed? Can you help me?

Thank you very much.