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MO: Fachverband Molekülphysik

MO 12: Kalte Moleküle 3

MO 12.1: Vortrag

Dienstag, 3. März 2009, 16:30–16:45, VMP 6 HS-G

Shaking of Feshbach molecules by nonresonant fields — •Mikhail Lemeshko and Bretislav Friedrich — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany

We propose to probe weakly-bound Feshbach molecules, both homo- and heteronuclear, by “shaking." This is based on the idea that a laser field can impart a tunable value of angular momentum to a molecule, via the interaction of the molecule’s anisotropic polarizability with the laser field. Thereby, a centrifugal term is introduced that can be set to a critical value sufficient to push the highest vibrational level of a Feshbach molecule out of the potential that binds it. The value of the critical angular momentum changes characteristically with internuclear distance. This can be used to map out the vibrational wavefunction of the highest vibrational state, by measuring the dissociation probability as a function of the intensity of a pulsed laser whose pulse duration is much shorter than the vibrational period. In turn, the vibrational eigenfunction can be inverted to yield the molecular potential with a high accuracy. We carried out numerical calculations for Rb₂ and KRb molecules using accurate potential energy surfaces and developed an analytic model of “dissociation by shaking" for several exactly solvable potentials. We note that the laser field of an optical dipole trap may actually be dissociating some of the most weakly bound molecules via the “shaking" mechanism.