Berlin 2005 – scientific programme
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MO: Molekülphysik
MO 24: Theory I
MO 24.9: Talk
Saturday, March 5, 2005, 16:00–16:15, HU 2097
How to measure the electron mass with two protons? — •Valenzuela Salazar Tristán, Senem Kilic, Jean-Philippe Karr, Remy Battesti, and Laurent Hilico — D’epartement de physique et modélisation, Université d’Evry, rue du père André Jarlan, 91025 Evry cedex, France
The vibrational energy levels of the H+2 molecular ion mainly depends on the very well known Rydberg constant and on the electron to proton mass ratio m/M. It is thus possible to measure directly this mass ratio from a spectroscopy experiment between to vibrational levels. Because H+2 is an homonuclear ion, one must use two photon spectroscopy. We have shown [Hil01] that one of the most favourable transition is the J=0, v=0 to v=1 infra red transition at 9.13 microns.
We have built a RF Paul trap for H+2 ion trapping. The v = 0 ions can be selected by UV photodissociation of the v>0 levels. The transition to the v=1 level will be excited using laser light at 9.13 microns and detected by UV photodissociation.
We are currently developping the 9.13 microns laser source. It is a quantum cascade laser (QCL) frequency locked to a stabilised C02 laser.
[Hil01] L. Hilico, N. Billy, B. Grémaud, and D. Delande Polarisabilities, light shifts and two-photon transition probabilities between J=0 states of the H+2 and D+2 molecular ions J. Phys. B 34, 491 (2001).