[CP2K:6288] Convergence problem wrt cutoff

[Matthias Krack]

A further observation: you specify PERIODIC NONE in the &CELL section, but 
there seems to be no &POISSON section with the same setting. 

Matthias

On Tuesday, 24 March 2015 19:03:45 UTC+1, Valérie wrote:
>
> Dear Matthias, 
>
> Thanks for the advice, I tried EPS_DEFAULT 1.0E-14 and turn off the 
> smearing but it didn't help:
>
> # Grid cutoff vs total energy
> # REL_CUTOFF = 100
> # Cutoff (Ry) | Total Energy (Ha) | NG on grid 1 | NG on grid 2 | NG on 
> grid 3 | NG on grid 4
>      50.00   -68.6591151507   51528     490       0       0
>     100.00   -71.4960225951   49423    2499      96       0
>     150.00   -71.3943595587   46649    4879     490       0
>     200.00   -71.4042101807   45019    6209     790       0
>     250.00   -71.4043240457   42959    7117    1846      96
>     300.00   -71.4043467391   41354    8069    2499      96
>     350.00   -71.4042672401   38632   10347    2847     192
>     400.00   -71.4043262818   37146   10913    3671     288
>     450.00   -71.4043453432   35187   11462    4879     490
>     500.00   -71.4043447554   34568   11773    5187     490
>     550.00   -71.4043353326   33159   11988    6081     790
>     600.00   -71.4043429773   32597   12422    6209     790
>
>
>
> On Tuesday, March 24, 2015 at 12:51:04 PM UTC-4, Matthias Krack wrote:
>>
>>  Dear Valerie, 
>>
>> you may try a smaller EPS_DEFAULT value like 1.0E-12 or even 1.0E-14. You 
>> may also switch off the smearing, if your systems shows a decent band gap. 
>> I would guess a cutoff of about 400 Ry should be sufficiently accurate.
>>
>> Matthias
>>
>> On 24/03/15 17:40, Valérie wrote:
>>  
>> Hi all, 
>>
>> I would like to run a geometry optimization of a single molecule with 
>> Quickstep but got stuck at the first step; i.e. get meaningful values of 
>> cutoff and relative cutoffs. 
>> I followed this tutorial: http://www.cp2k.org/howto:converging_cutoff 
>> but the total energy does not converge to great accuracy with my system:
>>
>> # Grid cutoff vs total energy
>> # REL_CUTOFF = 100
>> # Cutoff (Ry) | Total Energy (Ha) | NG on grid 1 | NG on grid 2 | NG on 
>> grid 3 | NG on grid 4
>>      50.00   -68.6591152269   51340     490       0       0
>>     100.00   -71.4960226714   49235    2499      96       0
>>     150.00   -71.3943596348   46461    4879     490       0
>>     200.00   -71.4042102566   44831    6209     790       0
>>     250.00   -71.4043241216   42771    7117    1846      96
>>     300.00   -71.4043468150   41166    8069    2499      96
>>     350.00   -71.4042673160   38450   10341    2847     192
>>     400.00   -71.4043263577   36970   10901    3671     288
>>     450.00   -71.4043454189   35016   11445    4879     490
>>     500.00   -71.4043448309   34404   11749    5187     490
>>     550.00   -71.4043354081   33007   11952    6081     790
>>     600.00   -71.4043430530   32450   12381    6209     790
>>
>> I was wondering if there was something I could try to fix this or should 
>> I carry on with Cutoff = 400?
>>
>> Many thanks
>> Valerie
>>
>>  
>>
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