Experimental transition probabilities for infrared lines of Cl I

Abstract

We operated a high-current, wall-stabilized arc in a gaseous mixture containing chlorine and observed $4s\text{\ensuremath{-}}4p$, $4p\text{\ensuremath{-}}4d$, and $4p\text{\ensuremath{-}}5d$ transitions in the red and near infrared spectrum. We measured their relative transition probabilities end-on and put them on an absolute scale with a lifetime value obtained from the literature. We achieved good agreement with recent sophisticated calculations and an earlier measurement for the stronger transitions, but encountered large differences for weak transitions.