The equilibrium structure of methyl fluoride

The equilibrium structure of CH3F has been determined using new sets of acc urate rotational constants that have been determined by taking into account all the interactions between the excited vibrational states. This experime ntal structure is in excellent agreement with the equilibrium geometry calc ulated at the CCSD(T) level of theory with the cc-pV(5, Q)Z basis set (incl uding corrections for the core correlation and for the effect of diffuse fu nctions on fluorine). Finally, the experimental and ab initio structures ha ve been combined by a least-squares analysis. The results are r(e)(C-H) = 1 .087 (1) Angstrom, r(e)(C-F) = 1.383 (1) Angstrom, and L-e(HCH) = 110.2 (1) degrees, where the uncertainties shown in parentheses correspond to three s tandard deviations.