The molecular constants of (CH3I)-C-12 in the ground and nu(6)=1 excited vibrational state

A set of 26 new measurements have been recorded by a Doppler-free double-resonance technique, with a relative accuracy of about 10(-8). These data are combined to previous FTIR measurements to refine the molecular constants of (CH3I)-C-12. All the available literature data have been revisited, a few assignments updated, and some frequencies changed according to new laser standards. A simultaneous fit to all the measurements of infrared, microwave, and radiofrequency transitions produced an improved set of parameters, independent of previously determined constants. (C) 1998 Academic Press