INFRARED DIODE-LASER MOLECULAR-BEAM SPECTRUM OF THE NU(2) BAND OF CHLORINE NITRATE AT 1293 CM(-1)

The nu(2) band of chlorine nitrate (ClONO2) near 1293 cm(-1) has been measured in a molecular beam with a diode-laser spectrometer. The low rotational temperature of the molecular beam, similar to 23 K, simplif ies the spectrum allowing essentially complete assignment of the Cl-35 and Cl-37 lines. An nib hybrid band is observed with the a-type trans ition moment being approximately a factor of 2 larger than the Lt-type transition moment. An inverted shift of the band origins is found wit h the Cl-37 band origin blue shifted From the Cl-35 by +0.37 cm(-1). T his isotopic shift is attributed to an unidentified anharmonic resonan ce. Precise spectroscopic constants for the bands of each isotopic spe cies are determined to allow future simulations for modeling atmospher ic transmission and for remote sensing applications. (C) 1997 Academic Press.