[CP2K-user] [CP2K:21265] Energy Instabilities in SCF Convergence of High Impact Energy Collisions

[Nicholas Laws]

Hi CP2K Community,

I hope this message finds you well. I am trying to perform a high energy 
collision of a fast incident neutral (EMI-BF4), which is composed of a 
cation (EMI+) and an anion (BF4-), and a surface. The "surface" is modeled 
as a harmonic potential set 10 Å away from the EMI-BF4 neutral. The EMI-BF4 
neutral travels into the harmonic potential at 70 eV, but begins to exhibit 
energy instabilities approximately 150 MD steps following collision. As a 
result, the fragmented species do not continue to propagate and equilibrate 
as expected. In my setup, I use the wB97X-D functional, an aug-cc-pVTZ 
basis set (chosen specifically for its diffuse functions to better describe 
the negative charge distribution and long-range interactions of BF4-), and 
all-electron potentials. To address the observed convergence issues, I have 
tried:

   1. Switching to DIAGONALIZATION in the SCF
   2. Increasing the number of added MOs (ADDED_MOS)
   3. Experimented with MIXING (Broyden) parameters

yet the SCF still struggles to converge reliably beyond the collision 
event. My goal is to obtain precise atomic partial charges on the 
post-collision fragments, ideally showing near-integer formal charges that 
reveal how the original cation and anion charges are redistributed.

I was curious if the community could suggest additional strategies or 
settings within CP2K that might stabilize the SCF convergence under these 
conditions? I’ve attached my input, output, and trajectory files in hopes 
that they clarify the nature of the instabilities.

Thank you very much for any guidance you can provide, and please let me 
know if there is any further information I can supply.

All my best,
Nick

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/cp2k/b2ad9bd5-aac1-4b70-b47f-4ba48f3492c2n%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20250306/9413a30c/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: EMIBF4_Surface_70eV.out
Type: application/octet-stream
Size: 3163664 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20250306/9413a30c/attachment-0001.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 70eV_EMIBF4_Surface_NVE-pos-1.xyz
Type: chemical/x-xyz
Size: 467810 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20250306/9413a30c/attachment-0001.xyz>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: EMIBF4_Surface_70eV.inp
Type: chemical/x-gamess-input
Size: 6379 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20250306/9413a30c/attachment-0001.inp>