Chemical and Magnetic Enhancement of Perturbed Lines in the Violet Spectrum of CN

Abstract

A chemical kinetic theory based on the quantum‐mechanical properties of perturbed molecular states is developed to explain the rotational intensity anomalies observed in the CN‐band spectrum emitted by an active nitrogen flame. Relative intensities of perturbed lines are calculated in terms of parameters which specify the rates of chemical formation, collisional relaxation, and radiative decay of CN molecules in the excited electronic states where the perturbed lines originate. Numerical values of these parameters are found which, inserted in the intensity expressions, predict correctly the observed pressure‐dependent enhancement of each perturbed line. From this analysis the approximate value 6×10^—7 sec is found for the radiative lifetime of the A²II_i, v′=10 state of CN. It is also found that nearly every gas kinetic collision changes the rotational state of an excited CN molecule, but that only about 1 collision in 100 can cause the exchange of vibrational energy for electronic energy represented by the transition A²II_i, v′=10→B²Σ⁺, v′=0. The theory also predicts, in agreement with recent observations, an additional selective enhancement of certain perturbed lines by a strong magnetic field.