JET-COOLED DIODE LASER SPECTRUM OF THE $\nu_{3}$ BAND OF $N_{2}O_{3}$ AT $1304 CM^{-1}$

Abstract

The jet-cooled spectrum of the $\nu_{3}$ (symmetric $NO_{2}$ stretch) band of $N_{2}O_{3} (NO_{2}$-NO mixed dimer) at $1304 cm^{-1}$ has been observed using an tunable infrared diode laser spectrometer. The spectrum was produced by expanding a mixture of 50 torr $NO_{2}, 150$ torr NO and 500 torr Ar through a $10 cm \times 25 \mu m$ continuous slit nozzle. About 65% of the region between $1299 cm^{-1}$ and $1310 cm^{-1}$ was covered using two diodes and transitions up to $J=20$ and $K=10$ were assigned. Transitions have a full-width at half maximum of 50 MHz and center freqencies are estimated to be accurate to $\pm 0.0002 cm^{-1}$. A total of 432 transitions were fit to three rotational and four distortion constants using the Watson A-reduced Hamiltonian with rms error of $0.0003 cm^{-1}$. A number of small perturbations were observed and the origin of these will be discussed.