[CP2K-user] Bulk phase vibrational spectra

Travis polla... at gmail.com
Wed Oct 28 20:24:15 UTC 2020


It doesn't look like either of these calculations ran to completion and 
towards the end of a3.out it is struggling to reach convergence. Though it 
looks like a2 just ran a little over the 1 ps mark, so it should be OK. I 
see in a3.inp you have increased your timestep to 2.5 fs which is almost 
certainly the cause of your instability. Reduce this to 0.5 fs and start 
from the end of a2 again. This is a very computationally expensive tutorial 
to run unfortunately to generate 30 ps. It may be beneficial to you to run 
the analysis at 10 ps into the production run and see if you can 
qualitatively reproduce the spectrum. You can keep running the trajectory 
in the background while doing this and stop it early if you're satisfied 
with the result from 10 ps.


On Wednesday, October 28, 2020 at 6:06:11 AM UTC-4 sum... at gmail.com 

> Hii,
> I am trying to calculate bulk phase vibrational spectra, for this I am 
> following a tutorial given on cp2k site. I use input files which are given 
> on "brehm-research.de/files/spec_tutorial_2018.pdf". 
> I have done "massive equilibration (2000 steps, 1ps) and global 
> equilibration (5000 steps, 2.5ps)" for a given coordinate file. I just want 
> to calculate IR spectra. So for this should i need to perform a 
> production run (60000 steps, 30ps) ?. 
> I have one more question: I am attaching the input and out file for both 
> the calculations. Did my jobs converge?
> Thanks, 
> sumit
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