Measurements of relative transition probabilities and the variation of the electronic transition moment for N₂C³Π_u-B³Π_gsecond positive system

Abstract

Accurate values of the relative transition probabilities A upsilon ' upsilon '' for 41 bands in the N 2 second positive system have been measured using single-photon counting techniques on a repetitive pulsed source. A computer code simulating the band structure, including multiplet splitting, and intensity distribution enables any band intensity to be deduced from the fractional intensity seen at the peak in the P branch (band-head). The variation of the electronic transition moment with internuclear separation R e (r) is obtained from the measured A upsilon ' upsilon '' by means of a weighted least-squares curve-fitting procedure based on nth moment r centroids. It is best represented by a polynomial of degree 2, (1-1.336r+0.487r 2 ) whose curvature is in the opposite sense to previously derived fits.