MULLIKEN CHARGE

[Matt W]

Hi,

apologies for patronising. Which published values are you comparing to?

At a glance your values don't look unreasonable to me.

Your input looks OK, except the cutoff is rather small - to get away with 
that small a value you need quite heavy smoothing of the XC - do the values 
change if you increase the cutoff?

Matt

On Monday, December 19, 2016 at 4:09:18 PM UTC, Josip Lovrić wrote:
>
> Dear Matt,
>
> I totally agree with you and I am aware of fact that atomic charge are 
> just model. 
> Maybe I was not clear enough but my problem is that charges are not 
> consistent with published values.
>
> P.S. input files are named "*_all_electrons*". This is mistake, 
> calculation is not all electron, it is a relict from previous calculation.
>
> Josip
>
> On Monday, December 19, 2016 at 5:03:50 PM UTC+1, Matt W wrote:
>>
>> Hi Josip,
>>
>> Mulliken charges are not real observables - they are strongly dependent 
>> on the basis set, and they do not converge as you make the basis set 
>> complete. Check a quantum chemistry textbook for a good discussion 
>> ('Computational Chemistry', Errol Lewars for instance).
>>
>> Something more quantitative can come from something like Bader charge 
>> analysis (which needs external processing of a total_charge_density cube 
>> file).
>>
>> Matt
>>
>> On Monday, December 19, 2016 at 3:56:55 PM UTC, Josip Lovrić wrote:
>>>
>>> Dear CP2K community,
>>>
>>> Recently I was working on NO2-dimer and now I need help from you. Thing 
>>> is that I am running gas phase calculation of NO2 cis-dimer. After program 
>>> successfully  finish GEOMETRIC OPTIMIZATION output configuration is 
>>> consistent with already published papers. Problem is in the MULLIKEN 
>>> charges. Charges are too small and not consistent with published values(I 
>>> am using same basis set).
>>>
>>> !-----------------------------------------------------------------------------!
>>>                      Mulliken Population Analysis
>>>
>>>  #  Atom  Element  Kind  Atomic population                           Net 
>>> charge
>>>        1     N        1          4.968657                             
>>>  0.031343
>>>        2     O        2          5.852787                             
>>>  0.147213
>>>        3     O        2          6.191534                             
>>> -0.191534
>>>        4     N        1          4.928901                             
>>>  0.071099
>>>        5     O        2          6.056358                             
>>> -0.056358
>>>        6     O        2          6.001764                             
>>> -0.001764
>>>  # Total charge                             34.000000                 
>>>  0.000000
>>>
>>>
>>>  !-----------------------------------------------------------------------------!
>>> I am using BLYP functional with dispersion corrections and TZV2P basis 
>>> set with pseudo-potentials. Charges are becoming more physical when 
>>> performing all electron calculation, they increase for factor ~10. 
>>> For DZVP basis set charges increase little, but still to low:
>>>
>>>  !-----------------------------------------------------------------------------!
>>>                      Mulliken Population Analysis
>>>
>>>  #  Atom  Element  Kind  Atomic population                           Net 
>>> charge
>>>        1     N        1          4.951639                             
>>>  0.048361
>>>        2     O        2          5.822911                             
>>>  0.177089
>>>        3     O        2          6.202144                             
>>> -0.202144
>>>        4     N        1          4.858609                             
>>>  0.141391
>>>        5     O        2          6.103330                             
>>> -0.103330
>>>        6     O        2          6.061367                             
>>> -0.061367
>>>  # Total charge                             34.000000                 
>>> -0.000000
>>>
>>>
>>>  !-----------------------------------------------------------------------------!
>>>   Am I doing something wrong? Do you have any explanation for this 
>>> results?
>>> I would really appreciate. 
>>>
>>> I am putting in attachment my input and output files. 
>>>
>>> Best wishes
>>> Josip
>>>
>>
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