THE FAR-INFRARED ELECTRONIC SPECTRUM OF NITRIC OXIDE

Abstract

The transition $X^{2} \Pi_{3/2}(v=0,J^{\prime})\leftarrow X^{2}\Pi_{1/2}(v=0,J)$ between the two components of the ground electrohic state of NO has been observed in the far infrared at $121 cm^{-1}$. A non-resonant cavity was used as a long-path cell in conjunction with a Michelson interferometer. Preliminary analysis of the R-branch lines of this band yields for the spin-orbit coupling constant the value $A_{0} = 123.18 \pm 0.06cm^{-1}$, in good agreement with results obtained from the satellite bands of the vibrational fundamental at 5 microns. The transition has also been observed in $^{15}N^{18}O$, and the isotopic dependence of $A_{0}$ will be discussed.