Michael Chrysos and his colleagues at the University of Angers (France) and the University of Saint Petersburg (Russia) have now derived the first exact mathematical formulas that can be used to calculate how collisions between molecules modify the absorption spectra for those molecules.
The absorption by single molecules is indeed governed by quantum laws, but absorption by molecules during collisions is, the new study shows, a process governed by classical laws of motion. You can read more about this problem in Physical Review Letters and the latest issue of Physics News Update.