Speaker
Description
The dissociation energy (D$_0$) of H$_2$ is a benchmark value in quantum chemistry, with recent QED calculations now approaching accuracies achievable in simple atoms. Precise measurement of the GK-X molecular transition, in combination with other precision measurements, provides a determination of D$_0$. The GK-X transition is excited through Doppler-free two-photon spectroscopy using 179-nm radiation, based on frequency up-conversion using a special KBBF crystal. The optical frequency of the fundamental (716 nm), which is the output of a narrowband pulsed Ti:Sa laser system, is locked to a frequency comb. This enables accuracies of the GK-X transition to a few parts in 10$^{10}$ or MHz level, leading to an order-of-magnitude improvement for D$_0$. The comparison of this accurate experimental result with the best calculations may provide a test of the Standard Model of Physics.
