Double resonance rotational action spectroscopy of cold H2D+ and D2H+

Abstract A double resonance action spectroscopic method has been applied to measure low- J rotational transitions of H 2 D + and D 2 H + up to frequencies of 1.5 THz. The uncertainties of two known lines of H 2 D + and three known lines of D 2 H + have been improved substantially, and the 2 11 ← 2 12 H 2 D + transition measured for the first time. In addition, we derived spectroscopic parameters for both molecular cations using the Euler formalism.