FTP, name this principle that suggests that the most favored excited state is that whose wavefunction is most similar to the ground state.
Llanes-Estrada, Cotanch, General, and Wang created an analogue of this statement in the momentum distribution of heavy-quark hadron decays, and a convenient visualization for this statement is the "parabola" named for its second namesake. This statement provided an explanation for Stokes' shift, that fluorescence band wavelengths are longer than absorption band wavelengths, and it functions as an extension to the Born-Oppenheimer approximation. This statement arises because nuclei are so much larger than electrons that they remain stationary on the timescale of photon absorption and emission, leading to vibrations, and it predicts electronic transitions to occur as the absolute square of the overlap integral, its namesake factor. FTP, name this principle that suggests that the most favored excited state is that whose wavefunction is most similar to the ground state.
Llanes-Estrada, Cotanch, General, and Wang created an analogue of this statement in the momentum distribution of heavy-quark hadron decays, and a convenient visualization for this statement is the "parabola" named for its second namesake.
{Franck-Condon} principle