[CP2K-user] Solid state DFT and vibrational analysis

[bobs your uncle]

Thanks Matt,

This is really what I have been looking for!

I'll give it a shot.

Cheers,
Fergus

On Tuesday, April 30, 2019 at 9:27:18 PM UTC+10, Matt W wrote:
>
> CP2K is a perfectly fine force / energy calculator. Lack of k-points and 
> symmetry might make things cumbersome. There is / used to be a wrapper for 
> phonopy which can be used to drive the phonon calculations. Lev 
> Kantorovich's Tetr / Lev00 also have some functionality.
>
> Have a look at this:
>
> https://www.cp2k.org/exercises:2017_uzh_cmest:phonon_calculation
>
> it might be useful.
>
> Matt
>
> On Tuesday, April 30, 2019 at 2:51:00 AM UTC+1, bobs your uncle wrote:
>>
>> Hi folks,
>>
>> Just a general question regarding vibrational analysis in an organic 
>> crystal using CP2K (just solid state DFT ignoring AIMD for now).
>> I thought about using more specialized software like quantum espresso - 
>> although I would prefer to use Crystal which I don't have access to 
>> currently - but the possibility of using CP2K for both solid state DFT, and 
>> later AIMD was more appealing to me for obvious reasons.
>> So first off, would you recommend CP2K for vibrational analysis of 
>> periodic systems? It would seem to me that it is uncommon, as I am having 
>> issues finding examples in the literature, and there aren't any guides 
>> either.
>>
>> To get to grips with CP2K, I first completed some of the tutorials as 
>> recommended before moving onto a "toy" system, where I have been attempting 
>> to reinvent the wheel with vibrational analysis. 
>> Of course, I would really like to know if anyone could advise me on the 
>> "right" way to do this. 
>> Currently, I start with a cell optimisation on an experimental crystal 
>> structure - following the sodium chloride guide on the CP2K website - then 
>> reoptimize the geometry with tighter convergence threshholds etc. 
>> I take that geometry and perform a vibrational analysis, and have 
>> succeeded in producing a complete set of real harmonics this way - which is 
>> a start - but I haven't been able to simulate some of the low frequency 
>> "terahertz" modes that have been reproduced in the literature (although for 
>> my system, the papers I can find don't talk at all about the software or 
>> process followed).
>> No one in my immediate academic circle is trained in these calculations, 
>> so I would really appreciate some of your wisdom if you could share it!
>>
>> Sorry, that was a bit of a read, but I'll put input files up if you are 
>> interested.
>>
>> Cheers
>>
>
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