CCL: Gen in gaussian

From: Roy Green <powergreen[a]gmail.com>
Subject: CCL: Gen in gaussian
Date: Fri, 4 Dec 2009 22:31:12 -0500

Hi, All
I tried to create a polar H-H' bond by altering the electronegativity of the hydrogen,H'. Of course such bond does not exist.
I did this by using different orbital exponent for the basis set centered on the two atoms. I am a little confused why the H atom with large orbital exponent bears more negative charges. My understanding is that the atoms with larger orbital exponent supposed to have more negative charges,since the more compact basis set is used for that atom. Could you please give me any suggestion?
The following is my input file and part of the output with the Mulliken charges.
Thank you.

Regards

Roy
cha


INPUT:

%chk=H.chk
%nprocshared=1
%Mem=50Mb
#P HF/Gen GFInput NoSymm pop=full

corner

0 1
H 0.0 0.0 0.0
H 0.0 0.0 0.75

1 0
S   1 1.00
      0.1000000000D+01 0.1000000000D+01
****
2 0
S   1 1.00
      0.8000000000D+00 0.1000000000D+01
****

OUTPUT:
...
Atomic charges with hydrogens summed into heavy atoms:
              1
     1 H    0.179398
     2 H   -0.179398
...