The equilibrium structure of methyl fluoride

The equilibrium structure of CH3F has been determined using new sets of accurate rotational constants that have been determined by taking into account all the interactions between the excited vibrational states. This experimental structure is in excellent agreement with the equilibrium geometry calculated at the CCSD(T) level of theory with the cc-pV(5, Q)Z basis set (including corrections for the core correlation and for the effect of diffuse functions on fluorine). Finally, the experimental and ab initio structures have 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 standard deviations.