J/ApJ/499/517 J/ApJ/499/517 Ethylene oxide spectrum J Pan S Albert K V L N Sastry E Herbst F C De Lucia Astrophys. J. 499 517 1998 1998ApJ...499..517P J/ApJS/117/427 : Sgr B2 spectral survey (Nummelin+, 1998) J/ApJ/500/1059 : Dimethyl ether transitions frequencies (Groner+, 1998) Atomic physics Spectroscopy ISM: molecules methods: laboratory molecular data radio lines: ISM The cyclic molecule ethylene oxide (c-C_2_H_4_O) has recently been detected in the interstellar source Sgr B2N. Previous laboratory work on the rotational spectrum of this molecule extends only to a frequency of 123GHz. We report here the extension of the laboratory rotational spectrum of this species through the frequency range 262358GHz using a new fast scan spectrometer (fast scan submillimeter spectroscopic technique, FASSST). The newly measured lines have been combined with previous data at lower frequencies to form a data set consisting of 662 lines that has been assigned and fitted via a standard semirigid asymmetric top analysis. The spectral constants obtained from the fit have allowed us to predict the frequencies of many additional lines.

J' J' rotational quantum number --- K'a K'a rotational quantum number --- K'c K'c rotational quantum number --- J" J" rotational quantum number --- K"a K"a rotational quantum number --- K"c K"c rotational quantum number --- FreqM Measured frequency MHz FreqC Calculated frequency MHz O-C Measured minus calculated frequency value MHz Ref References number=1 1: Hirose, 1974ApJ...189L..45H 2: Creswell & Schwendeman, 1974, Chem. Phys. Lett. 27, 521 The lack of a reference indicates that the line is reported here for the first time --- J' J' rotational quantum number --- K'a K'a rotational quantum number --- K'c K'c rotational quantum number --- J" J" rotational quantum number --- K"a K"a rotational quantum number --- K"c K"c rotational quantum number --- Freq Frequency MHz e_Freq rms uncertainty on Freq MHz mu2S Intensity ({mu}^2^S) number=1 S-value (Townes & Schawlow, 1975, Microwave Spectroscopy (New York: Dover)) multiplied by the square of the dipole moment D+2 Eu Upper state energy cm-1 James Marcout, Patricia Bauer CDS 1999Mar09 UNKNOWN UNKNOWN From ApJ electronic version J_ApJ_499_517.xml