Rovibronic coupling denotes the simultaneous interactions between rotational, vibrational, and electronic degrees of freedom in a molecule. When a rovibronic transition occurs, the rotational, vibrational, and electronic states change simultaneously, unlike in rovibrational coupling

Rovibrational coupling

Rovibrational coupling is a coupled rotational and vibrational excitation of a molecule. It is different from rovibronic coupling, which involves a change in all of electronic, vibrational, and rotational states simultaneously....

. The coupling can be observed spectroscopically and is most easily seen in the Renner-Teller effect

Renner-Teller effect

The Renner–Teller effect or Renner effect is an effect due to rovibronic coupling on the electronic spectra of three- atomic linear molecules in degenerate electronic states....

in which a linear polyatomic molecule is in a degenerate electronic state and bending vibrations will cause a large Rovibronic coupling.