title: Transition probabilities of a string oscillator subject to impulsive collisions with a heavy mass point.
abstract: Impulsive linear collisions between a string oscillator (a one-dimensional particle in a box) and a mass point are studied quantum mechanically. In the limit of a very heavy mass point (which corresponds classically to many collisions during a single encounter) the transition probabilities are determined exactly. The result permits a discussion of the mixed quantum-classical regime where the collider becomes almost classical while the oscillator remains quantum mechanical. While the average transition probabilities P(m-->n) are well reproduced by the Ehrenfest mean-field approximation, the prediction for the superimposed high-frequency resonance structure is qualitatively wrong for a genuine quantum oscillator. Only if the oscillator is also almost classical and if (m-n)2 square root(mu) << m, where mu is the mass ratio collider/oscillator, this structure is correctly predicted by the Ehrenfest approximation.
authors.affiliation: Max-Planck-Institut für biophysikalische Chemie, Postfach 2841, 37077 Göttingen, Germany. mteubne@gwdg.de
authors.forename: Max
authors.initials: M
authors.lastname: Teubner
mesh_terms: D002627:Chemistry, Physical / Q000379:methods*; D003198:Computer Simulation; D015233:Models, Statistical; D008962:Models, Theoretical; D009991:Oscillometry / Q000379:methods*; D055585:Physical Phenomena; D010825:Physics; D011336:Probability; D011789:Quantum Theory