Abstract
The (3) electric-quadrupole transition of the (3-0) overtone of molecular hydrogen has been recorded with a continuous-wave cavity ring-down spectrometer and calibrated with sub-megahertz accuracy using a temperature-stabilized Fabry-Pérot interferometer. The collision-induced frequency shift and the frequency at zero pressure limit are derived from a fit of the spectral profiles. The absolute transition frequency of the (3) line is determined to be 376 531 818.1 MHz with a 1.6-MHz accuracy () by measuring the shift to a Rb line at 795 nm. As the best determined transition frequency of neutral H in the ground electronic state, this value agrees well with recent high-level quantum chemistry calculations including relativistic and quantum electrodynamics corrections.
- Received 9 January 2012
DOI:https://doi.org/10.1103/PhysRevA.85.024501
©2012 American Physical Society