High-resolution infrared and infrared radiofrequency double-resonance spectroscopy of the ν2 band of CD 3I

Abstract

Approximately 175 transitions in the ν 2 band of CD 3I near 949.360 cm −1 have been recorded at Doppler-limited resolution and 2–10 MHz accuracy by means of an infrared microwave sideband laser spectrometer. About 150 radiofrequency resonances, half each in the ground and v 2 = 1 states, have been recorded at 70 kHz resolution and 5–20 kHz accuracy by using the infrared microwave sideband system as a pumping source for infrared radiofrequency double resonance. In addition to demonstrating the usefulness of this technique for systematic infrared radiofrequency double resonance, the radiofrequencies have been combined with previous measurements of microwave, millimeter-wave, and infrared radiofrequency double-resonance spectra to determine nuclear quadrupole coupling parameters, including centrifugal distortion effects, and spin-rotation parameters for the iodine nucleus. The infrared frequencies have been converted to hypothetical unsplit frequencies and combined with similarly converted microwave and millimeter-wave frequencies to obtain improved rotational and centrifugal distortion constants for the ground and v 2 = 1 states in CD 3I. These constants have been used to calculate coincidences with CO 2 laser frequencies for J ≤ 40 and K ≤ 10 and to assign three previously reported submillimeter-wave laser transitions.