[CP2K-user] Some questions on vibrational analysis

[Stephen]

Hi Azade, 

I share similar questions. 

Stephen 

On Wednesday, October 7, 2020 at 3:47:02 AM UTC-4 aza... at gmail.com 
wrote:

> Dear CP2K community,
>
> I am very new to the vibrational spectroscopy and its implementation with 
> CP2K. I tried to learn as much as I could from the previous conversations 
> and tutorials but there are still a few points which are unclear to me and 
> I hope you can help me with.
>
> I want to study the vibrational spectra of CO molecules on a Pd slab, for 
> various surface coverage. I use a dx value of 0.001A, EPS_DEFAULT 1.0E-12 
> and EPS_SCF 1.0E-10. My questions are the following:
>
> - When I have several CO molecules on the surface, would it make more 
> sense to use the 'INVOLVED_ATOMS' command for only one of the molecules or 
> all of them? My slab is  a 4x4, 5 layers, and I have a maximum of 8 CO 
> molecules on the surface.
>
> - In the output I get the following frequencies. Should I try to have all 
> such frequencies converged? If not, what do the ones which have not 
> converged mean? because when I use molden to look at the vibration modes, 
> the ones which have not converged are also present there, and I can see 
> their vibrational mode.
>
>   VIB|     61.573     0.004846      0.875E-07          0.440E-06           
> YES
>   VIB|    339.290     0.036719      0.409E-06          0.206E-05           
> NO
>   VIB|    652.872     0.001844      0.125E-05          0.424E-05           
> NO
>   VIB|    770.697     0.006918      0.198E-05          0.669E-05           
> NO
>   VIB|    875.719     0.009690      0.136E-05          0.686E-05           
> NO
>   VIB|   1005.729     0.018816      0.949E-06          0.478E-05           
> NO
>   VIB|   1136.781     0.002440      0.148E-05          0.501E-05           
> NO
>   VIB|   1235.179     0.010595      0.101E-05          0.509E-05           
> NO
>   VIB|   1309.728     0.013191      0.167E-05          0.565E-05           
> NO
>   VIB|   1392.711     0.023142      0.900E-06          0.453E-05           
> NO
>   VIB|   1549.969     0.048768      0.437E-05          0.148E-04           
> NO
>   VIB|   1634.615     0.011538      0.126E-05          0.636E-05           
> NO
>   VIB|   1654.494     0.026674      0.106E-05          0.357E-05           
> NO
>   VIB|   1774.636     0.014966      0.445E-06          0.224E-05           
> NO
>   VIB|   1824.832     0.028171      0.743E-06          0.251E-05           
> NO
>   VIB|   1861.463     0.022726      0.311E-06          0.156E-05           
> YES
>   VIB|   1895.821     0.014546      0.352E-06          0.119E-05           
> YES
>   VIB|   1942.303     0.549826      0.229E-06          0.115E-05           
> YES
>   VIB|   1995.758     0.002431      0.178E-07          0.601E-07           
> YES
>   VIB|   2004.175     0.000370      0.339E-07          0.171E-06           
> YES
>   VIB|   2172.351     0.006782      0.137E-10          0.692E-10           
> YES
>   VIB|   2182.669     0.015607      0.129E-10          0.651E-10           
> YES
>
> Sorry if my questions are more towards interpreting the output than 
> performing the test itself. Any explanations are highly appreciated. 
>
> Best regards,
> Azade
>
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