Dear Yang, It is correct that: (1) cp.x uses periodic boundary conditions, and (2) the atomic positions can evolve outside of the unit cell. The latter is a choice to make continuous the CPMD trajectory (which is handy when it comes to analyzing dynamical properties such as diffusion) and does not affect the correctness of the underlying electronic structure calculation. As such, it is not a problem per se; one can always post-process the trajectory to wrap the atoms back into the unit cell.
Best, Hsin-Yu -- Hsin-Yu Ko Postdoctoral Research Fellow Department of Chemistry and Chemical Biology Cornell University ________________________________ From: users <[email protected]> on behalf of 杨庆 via users <[email protected]> Sent: Wednesday, April 20, 2022 10:13 PM To: users <[email protected]> Subject: [QE-users] about the boundary in cp.x Dear qe users: Now i am dong cpmd in cp.x ,but i do not know how to control the boundary.i have learned that the default boundary in qe is pbc,but when i use 'verlet',the atoms run out of the box,how can i solve this problem?
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