ROVIBRATIONALLY RESOLVED, FOURIER-TRANSFORM NEAR-INFRARED SPECTROSCOPY OF THE NU(1) AND NU(2) VIBRATIONS OF THE HCL DIMER IN A SUPERSONIC JET

We have recorded the high-resolution (0.007 cm(-1)) Fourier-transform near infrared absorption spectrum of the symmetric Cl-35-Cl-35, and th e mixed Cl-35-Cl-37 isotopomers of the hydrogen chloride dimer in a su personic jet. The spectrum was recorded under a low effective rotation al temperature (approximate to 20 K). Rovibrational analysis of the ob served spectra has been performed for the K''(a)=0 subbands of the nu( 1)(+) and nu(1)(-) perpendicular-type bands centered at 2890 and 2879 cm(-1) respectively. The K''(a)=0 and 1 parallel-type subbands of the nu(2)(-) at 2839 cm(-1) and nu(2)(+) at 2857 cm(-1) have also been ana lyzed. Furthermore, we have observed and investigated the (H Cl-35)(2) nu(1)(+), K''(a)=1, Delta K= -1 rovibrational transition centered nea r 2869 cm(-1). The results are compared with spectra previously record ed using difference frequency tunable laser spectrometers both in a su personic slit jet and in an equilibrium gas phase mixture to demonstra te the advantages and limitations of the FTIR technique.