Sciencemadness Discussion Board

Assigning electronic transitions

kemfys - 9-4-2015 at 00:34

How do we find the what kind of electronic transition it is for a molecule computationally? How do we arrive at any of the following transition for any UV-Vis spectroscopy of organic molecules.

σ → σ*
π → π*
n → σ*
n → π*


Can someone please tell me how it is done.

smaerd - 9-5-2015 at 05:58

What soft-ware suite are you using? I'm not a computational chemist but I'm pretty confident these can be derived from DOS data. So, one could use say GAMESS under a UVVIS experiment get the DOS from Gassum or Gabedit and do the more involved analysis via another soft-ware. I'm not sure if there's a cookie cutter way about it.

TianjinLover - 4-11-2015 at 09:05

to get data of UV-Vis via Computation,TD-DFT is useful.Time-dependent density functional theory.Gaussian could be adopted to perform TD-DFT.
For reference:
https://en.wikipedia.org/wiki/Time-dependent_density_functio...