Speaker
Description
Molecular hydrogen, including its radioactive tritium-containing isotopologues, is a testing ground for quantum calculation in molecules. High precision coherent anti-Stokes Raman scattering (CARS) measurements were performed on the Q-branch fundamental vibrational splittings of heavier tritium-containing isotopologues, T$_{2}$ and DT with an uncertainty < 0.0004 cm$^{-1}$, a 250-fold improvement over previous work. These measurements are compared to first-principles calculations with improved treatment of nonrelativistic, relativistic and quantum electrodynamic energy contributions, with a total uncertainty of 0.00011 cm$^{-1}$ for DT. The experimental results showed good agreement with the calculations, yielding an averaged difference < 0.0002 cm$^{-1}$ that is below the combined uncertainty. High precision studies on these heavier species could help disentangling various mass-dependent terms in the calculations.