Oscillator Strength of the CN Red System

The red system of CN is produced in emission by running a pulsed electrodeless discharge in acetonitrile. The extrapolation at zero acetonitrile pressure of the fluorescence decay time is accepted as the lifetime of the A 2Π state of CN. The lifetime values vary slightly from one vibronic level to another. The dependence of the electronic part of the transition moment over the nuclear coordinates is deduced from this variation. A value of 3.4×10−3 is recommended for the oscillator strength f(0, 0) of the CN red system.