FranckCondonÜbereinstimmung

FranckCondonÜb is a theoretical concept in quantum mechanics used to describe the probability of electronic transitions in molecules. It is an extension of the Franck-Condon principle, which states that electronic transitions occur much faster than nuclear vibrations. This means that during an electronic transition, the positions of the nuclei remain essentially unchanged.

The Franck-CondonÜb principle, however, introduces the notion of "Übergangsdichte," or transition density, which accounts for the vibrational wavefunctions of both the initial and final electronic states. It quantifies the overlap between these vibrational wavefunctions. A larger overlap indicates a higher probability of the transition occurring. This overlap is calculated using integrals that involve the vibrational wavefunctions of the initial and final states.

In simpler terms, FranckCondonÜb helps predict which vibrational states a molecule will end up in after absorbing or emitting light. While the basic Franck-Condon principle focuses on the vertical transition, FranckCondonÜb provides a more nuanced understanding by considering the nuances of vibrational coupling. This concept is particularly important in spectroscopy, photochemistry, and understanding the dynamics of light-matter interactions. It allows scientists to interpret experimental spectra and predict the outcomes of photochemical reactions with greater accuracy.