Dear Benjamin
Without enetering the details of your calculations,
the Mulliken analysis gives numbers that can be very
sensitive to the basis set used.
Emilio
Benjamin Rogers wrote:
Dear All,
I am attempting to perform Mulliken analysis on some molecular
systems, however I am becoming confused by the output of Siesta. As
an example, consider the Mulliken output from the calculation of water
using the pseudopotentials and input file provided in the examples
folder. This indicates a valence charge on the oxygen of 5.717 and a
valence charge on each hydrogen of 1.142. This seems to disagree with
conventional thought of the oxygen atom having a high
electronegativity, which would result in it having a valence charge
above 6 in water.
In addition, Mulliken analysis from GAMESS given at
http://www.chem.swin.edu.au/modules/mod5/annot_h2o_g.html indicates a charge on
oxygen of 8.274 (a valence charge of 6.274) and a charge on hydrogen of 0.863.
This appears to conform to the conventional description of water, and is
therefore as expected.
Can anyone please explain the Siesta results?
Thank you in advance,
Ben.
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