THE MILLIMETER-WAVE AND SUBMILLIMETER-WAVE SPECTRUM OF ETHYLENE-OXIDE(C-C2H4O)

The cyclic molecule ethylene oxide (c-C2H4O) has recently been detecte d in the interstellar source Sgr B2N. Previous laboratory work on the rotational spectrum of this molecule extends only to a frequency of 12 3 GHz. We report here the extension of the laboratory rotational spect rum of this species through the frequency range 262-358 GHz using a ne w fast scan spectrometer (FASSST). The newly measured lines have been combined with previous data at lower frequencies to form a data set co nsisting of 662 lines that has been assigned and fitted via a standard semirigid asymmetric top analysis. The spectral constants obtained fr om the fit have allowed us to predict the frequencies of many addition al lines.