Rovibronic coupling

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. The coupling can be observed spectroscopically and is most obviously in the Renner-Teller effect in which a linear polyatomic molecule is in a degenerate electronic state and bending vibrations will cause a large Rovibronic coupling.