Title: Identification and Non-destructive State Detection of Molecular Ions Speaker: Matthias Keller University of Sussex, Brighton Time: Thursday, December 15th, 15.15 to 16.00 Place: Aud. G2 (1532) Abstract: Cold molecules have a multitude of applications ranging from high resolution spectroscopy and tests of fundamental theories to cold chemistry and, potentially, quantum information processing. Prerequisite for these applications is the cooling of the molecules? motion and its non-invasive identification. Furthermore, the internal state of the molecules needs to be prepared and non-destructively detected. The cooling of the motion and trapping of molecular ions can be accomplished by trapping them in an rf-trap alongside laser cooled atomic ions. We have developed a novel technique to measure the average charge to mass ratio of trapped ions with high precision by broadband excitation of the ions' COM-mode motion and measuring their laser induced fluorescence. The FFT of the fluorescence?s autocorrelation provides the COM-mode spectrum with a good SNR for measurement times as low as 100ms and kinetic energy injections of less than a few mK. We have employed this method to observe charge exchange reactions between different calcium isotopes. Due to the precision the small temperature increase, we were able to measure the anharmonicity of the trapping potential and the configuration shift in mixed ion strings. The method is limited only by the required interrogation time and the motional coupling of the constituents of the mixed ion crystal. While blackbody assisted laser cooling was recently demonstrated, the non-destructive state detection is still beyond current experiments. Employing state selective laser induced dipole forces we aim to detect the internal state of molecular ions by mapping the state information onto the ions' motion. The scheme promises mitigation of the effect of laser polarisation and the distribution of population across Zeeman sublevels and it may be applicable for a larger number of simultaneously trapped molecules. Jacob Sherson and Aurélien Dantan Coffee, tea and cake will be served at 15.05 ----------------------------------- Aurelien Dantan Ion Trap Group Department of Physics and Astronomy University of Aarhus Ny Munkegade, bygn. 1520 8000 Aarhus Denmark +4589423602