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Q: Quantenoptik
Q 221: Teilchenoptik
Q 221.4: Vortrag
Dienstag, 5. März 2002, 17:15–17:30, HS 22/B01
Matter Diffraction and Spectroscopy of Very Weakly Bound Molecules — •M. Stoll, G.C. Hegerfeldt, and T. Köhler — Institut für Theoretische Physik, Universität Göttingen, Bunsenstraße 9, 37073 Göttingen
In order to verify the existence of the so called Efimov state in the helium trimer He3, Hegerfeldt and Köhler suggested to produce it from ground state trimers by excitation from the transmission grating in a diffraction experiment [1]. The diffraction angles shift in a characteristic way since the kinetic energy is reduced by the excitation energy.
The theory is now being carried over and applied to the van der Waals dimer (D2)2 which has four (weakly bound) rotational states. Due to symmetry the parity of the dimer state is conserved during the excitation. Starting from the theory of molecular diffraction introduced earlier [2] a formula for the diffraction peak intensities is derived. It shows that the excitation probabilities can be as large as 1%.
With a sensitive detector the present method makes the spectroscopy of weakly bound van der Waals molecules experimentally feasible.
[1] G. C. Hegerfeldt, T. Köhler, Phys. Rev. Lett. 84, 3215 (2000)
[2] R. E. Grisenti, W. Schöllkopf, J. P. Toennies, G. C. Hegerfeldt, T. Köhler, M. Stoll, Phys. Rev. Lett. 85, 2284 (2000)