Hello,
I calculated a cation molecule with gaussian 09.
Based on the output file, how can I determine which atom has a charge?
In Gaussian view, N atom has 4 bonds, so it might have + charge.
What I want to know is that in the output file of this calculation, is it contains information which atom has charge?
If so, where can I find that?
Thank you :)
Dear Lucy Ryou , In the G09 output file, the section Mulliken charges and spin densities denotes the Mulliken charge for each atom. But, Mulliken charges are highly influenced by the basis set used and so have no relation to physical charges. I strongly recommend performing NBO analysis in G09 to generate more meaningful charges. In this case, use the keywords pop=(nbo,savenbos) for the input, and charges are availaibe in the section Summary of Natural Population Analysis in the output.
Also I suggest the MEPs approach (mapped molecular electrostatic potential) .
Regards,
In GaussView, you can check the charge distribution for each atom. There are several ways to calculate the charge, i.e., Mulliken, npa ....... Choose depending on your analysis object, such as Fukui, ESP etc.
You just found it in result summary where there is written a doublet....Doublet means spin multiplicity is 2(S)+1 =2
If you open the output file of this cationic molecule by Gaussview or Avogadro, you can find an atom that has an extra bond.
For example, in Rhodamine B as a cationic dye, one of the nitrogens has an extra bond (4 bonds) and so a positive charge.
So in the output file, you have: charge(+1) and multiplicity(2)
(S for a cation is 1/2 and multiplicity is 2S+1)
In fact, there is no way to specify the charge in an individual atom by output file but you can use Parr functions (“Parr functions” were introduced by Luis R. Domingo) to predict the most reactive sites and computing the electrophilic and nucleophilic Parr functions of a molecule is an easy task with Gaussian program.
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