CARS spectroscopy of the ( v = 0 1 ) band in T 2

Molecular hydrogen is a benchmark system for bound state quantum calculation and tests of quantum electrodynamical effects. While spectroscopic measurements on the stable species have progressively improved over the years, high-resolution studies on the radioactive isotopologues T 2 , HT and DT have been limited. Here we present an accurate determination of T 2 Q ( J = 0 – 5 ) transition energies in the fundamental vibrational band of the ground electronic state, by means of high-resolution coherent anti-Stokes Raman spectroscopy. With the present experimental uncertainty of 0.02 cm − 1 , which is a fivefold improvement over previous measurements, agreement with the latest theoretical calculations is demonstrated.