Long-lived K a=0, 2B1 states of NO2: A direct measurement using a tunable dye laser

Abstract

Narrow‐band (1 GHz) excitation coupled with selection of specific emission bands has been used to measure the lifetimes of some K_a=0, ²B₁ states of NO₂. In contrast with previous experiments and expectations of short lifetimes based on analysis of possible perturbations in the electronic manifold, these states exhibit long collisionless lifetimes of 33±4 μsec. Their quenching cross sections are found to be larger than gas kinetic, and much larger than that for the unresolved fluorescence.