SUB-DOPPLER HETERODYNE FREQUENCY MEASUREMENTS NEAR 5 MU-M WITH A CO-LASER SIDE-BAND SYSTEM - IMPROVED CALIBRATION TABLES FOR CARBONYL SULFIDE TRANSITIONS

We present a series of sub-Doppler frequency measurements of carbonyl sulfide (OCS) rovibrational transitions covering the spectral region a round 2050 cm(-1) (61 THz). The absolute experimental uncertainties ar e between 21 and 84 kHz (Delta v/v = 3-14 X 10-(10)). In our spectrome ter, tunable microwave sidebands are added to GO-laser lines and are u sed to saturate OCS transitions at low absorber pressure. The CO laser , plus a fixed-frequency sideband, is stabilized to the center of the OCS Lamb-dip signal and the laser frequency is measured against combin ation frequencies of two saturation-stabilized CO2 lasers. The determi ned OCS transition frequencies are combined with other data in a least -squares fit. These measurements improve the accuracy of several carbo nyl sulfide bands for calibration purposes by one to two orders of mag nitude. New molecular constants and detailed calibration tables betwee n 860 and 3100 cm(-1) are given. (C) 1996 Academic Press, Inc.