[CP2K:4905] Charge calculation -- Charged system

hut... at chem.uzh.ch hut... at chem.uzh.ch
Tue Jan 21 08:19:47 UTC 2014


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.


Juerg Hutter

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

-----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  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. 


 #  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.  



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