Radiative lifetimes and two-body collisional deactivation rate constants in Ar for Xe(5p56p),Xe(5p56p), and Xe(5p57p) states

Abstract

The radiative lifetimes and collisional deactivation rate constants by argon of four Xe(5p ⁵[²P_3/2]6p), three Xe(5p ⁵[²P_1/2]6p), and three Xe(5p ⁵[²P_3/2]7p) levels, hereafter referred to as Xe(6p), Xe(6p′), and Xe(7p) states, have been measured by a time‐resolved laser‐induced fluorescence technique in a flowing afterglow apparatus. The deactivation rate constants of the 6p levels are in the (0.5–5)×10⁻¹¹ cm³ s⁻¹ range; however, the rate constants for the 6p′ and 7p levels are much higher with values of (15–40×10⁻¹¹ cm³ s⁻¹. Product states resulting from two‐body collisions between the laser excited Xe(6p, 6p′, and 7p) atoms and ground state argon atoms were identified from the product emission spectra. In addition to intramultiplet relaxation, considerable intermultiplet transfer to the 6s′ levels seems to occur for the Xe(6p) states. Both intramultiplet relaxation and intermultiplet transfer (to the 6d, 5d, and 7s manifolds) are important for the Xe(6p′) and Xe(7p) states. Radiative branching ratios for emission in the 450–1100 nm range were measured for several levels. In some cases these ratios can be combined with radiative lifetimes to provide absolute transition probabilities. The lack of reliable branching ratios for the transitions in the infrared is a serious deficiency which prevents the assignment of absolute transition probabilities and also affects the kinetic interpretations for product formation processes.