Hamburg 2009 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

MO: Fachverband Molekülphysik

MO 9: Femtosekundenspektroskopie 3

MO 9.1: Talk

Tuesday, March 3, 2009, 16:30–16:45, VMP 6 HS-F

Observation of vibrational wave packet dynamcis in a single isolated molecular ion — •Steffen Kahra, Günther Leschhorn, Hsiang-Tai Dou, Wolfram Schmid, Werner Fuß, and Tobias Schaetz — Max-Planck-Institut für Quantenoptik, Garching

Encouraged by the present and still improving excellent temporal resolution of short laser pulses in the UV (< 4 fs) [1] our TIaMo-project focuses on the combination of temporal control in the optical domain with precise methodology of molecular ions in a Paul trap. Our set-up has been layed out for various pump-probe experiments ranging from X-ray diffraction to spectroscopy in the visible.

We present the current experiment that should allow us to observe vibrating molecular ions. The present scheme bases on MgH⁺ ions albeit other molecular ions of interest and suitable size could be loaded, too. A pulse around 270 nm creates an oscillating wave packet. By absorption of another time delayed UV photon a dissociative channel becomes accessible depending on the position of the wave packet [2]. Thus the dissociation probability is expected to be modulated by the pump-probe delay and is proposed to reflect the molecular vibrational period of 31 fs. The speciality of our concept lies in the target consisting of only one or few isolated molecular ions embedded in a laser cooled fluorescing Mg⁺ ion crystal. Our detection method exploits the non-fluorescence of MgH⁺ occupying crystal lattice sites and enables us to count the modulated number of dissociated dark molecular ions.

0mm [1] U. Graf et al., Opt. Express, 2008, 16, 18956-18963

[2] S. Jørgensen et al., J. Chem. Phys., 2005, 123, 094302-9