Microwave spectrum and structure of ethylene ozonide: Effects of large axes rotations in structure calculations

Rotational spectra for 14 isotopic species of ethylene ozonide have now been assigned. The consistency of the Kraitchman substitution structure was checked by calculating the O_p---O_p bond distance six ways; the values ranged from 1.458 to 1.502 Å. This variation was attributed to an amplification of residual vibrational effects by large axes rotations upon isotopic substitution. Estimates of errors produced from this effect were made and a procedure was developed for choosing r_s parameters in which the effect is minimized. This gave the following ring parameters: d(CO_e) = 1.416 Å, d(CO_p) = 1.412 Å, d(OO) = 1.461 Å, <CO_eC = 104.8°, <O_eCO_p = 105.5°, <CO_pO_p = 99.3°.