[CP2K:4905] Charge calculation -- Charged system

[hut... at chem.uzh.ch]

Hi

you are calculating a water molecule with a distant proton.
GGA functionals are known to get this wrong. They fail to
localize the charge and give a 'smeared' charge distribution.
See the 0.5 charge on the lone H. 
HF on the other hand localizes the charge, as you can see in
your Gaussian calculation.

regards

Juerg Hutter

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Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie                  FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
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-----cp... at googlegroups.com wrote: -----
To: cp... at googlegroups.com
From: Sandeep Kumar Reddy 
Sent by: cp... at googlegroups.com
Date: 01/21/2014 06:55AM
Subject: [CP2K:4905] Charge calculation -- Charged system

Dear All,
                 I am trying to calculate atomic charges of a system whose total charge is +1. I am not able to get charges correctly as expected. 

For the sake of better understanding, i have taken an easy system which consists of 1 water molecule and 1 H atom (Total 4 atoms).  

First, I used Gaussian software to calculate the atomic charges on this system. 

 Mulliken atomic charges: (Method:  hf 6-31g(d))
              1
      1  O   -0.857873
     2  H    0.424054
     3  H    0.433819
     4  H    1.000000

 Sum of Mulliken atomic charges =   1.00000


 
Using CP2K, i have got the following charges. 

MULLIKEN POPULATION ANALYSIS

 #  Atom  Element  Kind  Atomic population                Net charge 
       1     O        1          5.956324                  0.043676
       2     H        2          0.814162                  0.185838
       3     H        2          0.809985                  0.190015 
       4     H        2          0.419529                  0.580471
 # Total charge                  8.000000                  1.000000


In case of atom centered basis set, i can clearly see +1 charge is localized on 1 H atom where as it is not the case using mixed basis set. Could anybody help me in this regard? The cp2k input file is enclosed.  

Thanks.

Regards,
Sandeep 



  
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[attachment "cp2k.inp" removed by Jürg Hutter/at/UZH]