This problem is irrelevant to the functions of Multiwfn. You need to optimize geometry of excited state by quantum chemistry program such as Gaussian and ORCA. For example, if your molecule is a closed-shell system, and you want to optimize S2 state, in Gaussian you can input e.g. # PBE1PBE/6-311G* TD(nstates=5,root=2) opt
I am trying to study the geometry of the excited states of a molecule. How to perform and get the excited state bond length and angle using the Multiwfn?
Thank you.