Ramsey-type microwave spectroscopy on CO ($a^3\Pi$)

A. J. de Nijs, W. Ubachs, H. L. Bethlem

Using a Ramsey-type setup, the lambda-doublet transition in the $J=1,\Omega =1$ level of the $a^3\Pi$ state of CO was measured to be 394 064 870(10) Hz. In our molecular beam apparatus,…