@article {heller1990mode, title = {Mode mixing and chaos induced by potential surface crossings}, journal = {The Journal of chemical physics}, volume = {92}, year = {1990}, pages = {1718{\textendash}1727}, publisher = {AIP Publishing}, abstract = {The effect of Born{\textendash}Oppenheimer potential energy surface crossings on energy transfer in polyatomic molecules is investigated, classically and quantum mechanically. The hopping from one energy surface to another is enough to cause classical chaos, and strong mixing of the levels quantum mechanically. The r a t e of classical mixing determines the e x t e n t of quantum mixing, even though classical mixing is complete at long times.}, url = {http://dx.doi.org/10.1063/1.458054}, author = {Heller, EricJ.} }