Study of atmospheric trace gases by sub-Doppler diode laser spectroscopy

Recent results of sub-Doppler infrared diode laser spectroscopy of freons in a supersonic jet are reported. The nu(1) parallel band of CCl3F has been recorded at a rotational temperature of about 20 K, in a supersonic slit jet expansion. A detailed rotational analysis has been performed yielding band origins and rotational constants for the three most abundant isotopomers (CCl3F)-Cl-35, (CCl2ClF)-Cl-35-Cl-37 and (CClCl2F)-Cl-35-Cl-37. The CHF2Cl molecule (freon 22) has two strong fundamental bands in the atmospheric window, nu(3) at 1108.7278 cm(-1) and nu(8) at 1127.2844 cm(-1). A preliminary analysis of the nu(3) band of the (CHF2Cl)-Cl-37 isotopic species will be presented.