High-Resolution Rotational Spectroscopy of CH3I Using a Novel Doppler-Free Technique

The Molecular Constants of12CH3I in the Ground andv6= 1 Excited Vibrational State

“…The experimental setup has already been described (13) and only a short presentation will be given here. The IR pump source is a cw waveguide CO 2 laser whose frequency is stabilized with a resolution of about 20 kHz and an absolute accuracy of about 50 kHz.…”

“…More recently in Pisa a new Doppler-free technique (13) has been used to measure the frequency of rotational and vibrational transitions. A preliminary result for the ground state is described in Ref.…”

Hyperfine Level Dependence of the Pressure Broadening of CH3I Rotational Transitions in the v6 = 1 Vibrational State

“…The main features of the apparatus have been discussed in Refs. (9,10), and only a short description of recent improvements will be reported here.…”

“…The intensity of laser radiation is modulated by a mechanical chopper, so the microwave radiation reaching the detector generates a signal that can be processed by a lock-in amplifier tuned to the chopper reference. Since the infrared and the microwave radiations propagate in the same direction, when the laser is tuned exactly to the vibrational resonance, a single Doppler-free lineshape is detected (10).…”

Microwave and submillimeterwave spectra of CH2DI and CHD2I

“…An experimental harmonic force field was obtained by Mallinson [27], an ab initio anharmonic force field was calculated by Schneider and Thiel [33], and the equilibrium structure was recently redetermined by Demaison et al [34]. For CH 3 I, the dipole moment [35,36] and the hyperfine constants [1,2] were repeatedly determined.…”