[CP2K-user] [CP2K:20743] Re: Gallium + CO2 lack of convergence

[Michela Benazzi]

Hi Marcella,

Thank you again!

1) should I run GEO_OPT on the pure Ga liquid, then add CO2?
2) How should I form a cavity artificially without disrupting the newly 
equilibrated Ga structure?
3) I only have one molecule of CO2 in there - How should I go about 
lowering the concentration? Should I just increase my #Ga atoms and add 1 
CO2 molecule?

Best,

Michela
On Thursday, October 3, 2024 at 10:20:25 AM UTC-4 Marcella Iannuzzi wrote:

>
> Dear Michela, 
>
> The procedure you describe  does not sound very appropriate to me. 
> You should first obtain a liquid system, without solute. 
> I suppose you should check for density and other properties and have a 
> sufficiently large box. 
> Then you can create a cavity in the equilibrated liquid and insert the 
> solute, still with the right C-O bond length.
> If the SCF does not converge anymore after a few steps it is probably 
> because of the coordinates. 
> The concentration of CO2 seems rather high. 
>
> You can use GAPW. It is more commonly used for all electron calculations. 
> With PP, GPW is as accurate.
>
> Regards
> Marcella
>
>
>
> On Thursday, October 3, 2024 at 3:02:10 PM UTC+2 bnzmi... at gmail.com wrote:
>
>> Hi Marcella,
>>
>> thank you for your kind response and your time.
>>
>> 1) I just switched to double zeta quality a few hours ago, but my MD just 
>> crashed because, weirdly, it converged for the first few SCF loops, but 
>> then it stopped converging (attached the output file here to explain).
>>
>> 2) I am using GAPW because I found that augmented plane waves method 
>> worked really well with my liquid Al systems before. that method is also 
>> reported in DFT literature for liquid Ga. Rationalizing it, I think it 
>> works because it samples regions of space with different charge densities 
>> with more accuracy. Do you think I should consider something else?
>>
>> 3) I used a cell size to represent the density of liquid Ga with the # of 
>> atoms I have. I prepared my coordinates with a Python script, then relaxed 
>> the geometry in Avogadro2 software and inserted CO2 such that it was a 
>> distance of min 2.5 A to minimize initial repulsion with Ga atoms. Do you 
>> have any suggestions to prepare a structure? I am leaving 1-2 A on all 
>> sides from the unit cell boundaries because I have been worried about Ga 
>> atoms being too close to neighbors across periodic boundaries.
>>
>> Michela
>> On Thursday, October 3, 2024 at 8:23:26 AM UTC-4 Marcella Iannuzzi wrote:
>>
>>> Dear Michela, 
>>>
>>> The basis set you are using is of poor quality. 
>>> The coordinates you sent show a rather strange C-O bond length
>>> The cell is very small, but still there is vacuum space among the 
>>> replicas in all directions, it is a rather weird choice of coordinates. 
>>>
>>> Is there a reason why you are using GAPW?
>>>
>>> Regards
>>> Marcella
>>> On Wednesday, October 2, 2024 at 7:27:59 PM UTC+2 bnzmi... at gmail.com 
>>> wrote:
>>>
>>>> Good morning dear CP2K community,
>>>>
>>>> how are you? You may know me from previous posts on liquid Al (+CO2) MD 
>>>> troubleshooting. All of your responses have been super helpful so far, and 
>>>> I am coming here again for a different liquid metal.
>>>>
>>>> My simulations with pure liquid Gallium have been less troublesome than 
>>>> all of my liquid Al simulations, but the MD with 1 CO2 molecule won't 
>>>> converge. Can I please get some help troubleshooting?
>>>>
>>>> Thank you,
>>>>
>>>> Michela
>>>>
>>>

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