Knowledge Bank

The radiofrequency spectrum of the $A3\Sigma +u$ state of $N2$ has been measured at low magnetic fields gauss) by means of the molecular beam magnetic resonance method. Resolved transitions between hyperfine levels with quantum numbers $F\to F-1$ have been observed for states with quantum numbers (N,J,F) equal to (0, 1,2), (1,2,4), (1,2,3), (2,1,2),(3,2,4), (3,2,3), and (3,2,2) in 13 different vibrational levels. The fine and hyperfine structure theory of a $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma$ state is developed to an accuracy of several KHz and used to interpret the measurements. Variation with vibration of the molecular parameters is presented and discussed.