Microwave Spectrum of Ethylene Oxide in Excited Vibrational States

In the rotational spectrum of ethylene oxide, the five lowest-lying vibrational states are assigned and the vibration-rotation constants and the centrifugal distortion constants are derived. The vibrational frequencies are estimated from relative intensity measurements at νa=803±18 cm−1 and νb=814±23 cm−1 for the antisymmetric species (with respect to the C2 operation) and at νc=872±34 cm−1, νd=1020±33 cm−1, and νe=1109±42 cm−1 for the symmetric species. The intensity measurements of the remaining spectral lines showed that these lines belong to vibrational states at frequencies above about 1000 cm−1. The νa, νb, and νc states are tentatively assigned to ν15, ν12, and ν5, respectively, by taking into account the Goriolis interactions.