[CP2K-user] GEO_OPT a molecular is 10000 time longer then gaussian

[Linfeng Gan]

Thank you very much Vladimir,

1) I know CP2K is not a choice for small molecules. But I am investigating 
an organic reaction which could take place in gas phase and on C3N4 
surface. I have to compare the data between the gas phase and the surface. 
So, I can’t use gaussian or orca to that. DMol3 or CASTEP maybe is best 
choice for me, but I think we should give open source software a chance. 
So, CP2K is my choice right now. I am not very familiar with CP2K that it’s 
why I go to this forum and ask for some help. 

2) Agree. 

3) Yes, it was. 

4) 10000 times is an exaggeration, I apologize for that. Form the same 
initial structure, it took gaussian 41 seconds with a single Xeon 2680v2 
CPU to finish the geometry optimization, but it took CP2k 40 minutes with 
20 CPU to do the same thing. If we include the frequencies calculation the 
time is 4 minutes vs 71 minutesX20CPU. A single SCF calculation of CP2K was 
pretty fast, but most of time was wasting in locating the minimize. 
This efficiency issue only happened in this 1-butene molecular. Another 
molecular I tested, cyclobutene, seemed much batter than 1-butene. 

I attach all the input and the output file. So, you guy can help me to 
improve this. Thanks all.


Best,
LInfeng


On Friday, May 15, 2020 at 7:41:12 PM UTC+8, Vladimir Rybkin wrote:
>
> Dear Linfeng,
>
> a few general remarks:
> 1) CP2K is not the most efficient tool for small molecules. For instance, 
> it does a lot of integrations over cells in real and reciprocal space, and 
> for a small molecule the cell is almost everywhere empty.
> 2) CP2K does not use internal coordinates for optimisation. This has to do 
> with the fact that it's mostly meant for large periodic systems. Gaussians' 
> Berny algorithm does use internal coordinates and is very efficient for 
> small systems.
> 3) It's very likely that you 150 steps have not change the geometry 
> significantly. 
> 4) It's not completely clear where this 10000 times come from. It may have 
> to do with how you compile and run your applications.
>
> That said, there's no specific problems with optimisers and efficiency. 
> It's about applicability of tools for specific purposes. If you going to 
> work with small molecules, you'd better stick to programs made for them, 
> i.e. Gaussian. CP2K is meant for large and/or periodic systems.
>
> Yours,
>
> Vladimir
>
> пятница, 15 мая 2020 г., 2:51:51 UTC+2 пользователь Linfeng Gan написал:
>>
>> Hi all,
>>
>> When I optimized 1-butene molecular at B3lYP/6-311G** level, it took much 
>> much longer than gaussian16 did.  I had test optimizer CG, BDGS and 
>> LBFGD, nothing better. It seems the optimizers have some efficiency issues. 
>> All three optimizer had taken at least 150 optimization steps to get the 
>> final structure, but the initial structure had been optimized by gaussian. 
>>   How could I improve that?
>>
>>  
>>
>> Best
>>
>> Linfeng
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20200516/998b3207/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OT_forum.zip
Type: application/zip
Size: 166053 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20200516/998b3207/attachment.zip>