In a molecular geometry calculation using a Gaussian program, can I see changes in bond lengths or changes in structure when one electron enters the molecule through a reduction reaction?

for example, I want to see reduction of Benezene.

First, optimize Bezene structure. calculation setup to Optimize(job type) and Ground state, DFT, Default spin, B3LYP(method), 6-31G, ++(2d,p), charge 0

After that, I proceeded with the calculation in the same way, but with charge set to -1.

Is it correct way to see change of Benzene structure after reduction?

  • 1
    $\begingroup$ yes, you can, assuming there is a geometry change. without specifics, it is hard to say anything more $\endgroup$
    – Greg
    Commented Nov 10, 2023 at 15:25
  • $\begingroup$ I've posted a revised version of how I calculated it, could you please double check? $\endgroup$
    – Jay Kim
    Commented Nov 14, 2023 at 9:50
  • $\begingroup$ Is the benzene radical anion really stable without a countercation (say Li+)? Chances are that the naked benzene radical anion will spontaneously ionize. Even if not, B3LYP is probably inappropriate since its exchange potential does not have the correct long range asymptotic behavior to describe the diffuse tail of the electron density. $\endgroup$
    – wzkchem5
    Commented Nov 18, 2023 at 11:55

1 Answer 1


Unless there is something I am misunderstanding, that should be fine. Just remember to change the multiplicity as well (technically, 'spin' is not part of a Gaussian input).


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