The equilibrium structure and fundamental vibrational frequencies of dioxirane

Complete sets of quadratic and cubic force constants calculated for four isotopomers of dioxirane (CH2OO) are used to estimate vibration-rotation interaction contributions to observed values of rotational constants (B″), thereby yielding empirical estimates of the corresponding equilibrium values (Be). At the highest levels of theory, least-squares refinements of atomic coordinates to both the empirical Be values and the associated isotope shifts yield consistent sets of structural parameters. Recommended values are re(CO)=1.3846±0.0005 A; re(OO)=1.5133±0.0005 A; re(CH)=1.0853±0.0015 A and θe(HCH)=117.03±0.20°. Semidiagonal quartic force constants (in the normal coordinate representation) a…