Collisional Quenching and Energy Transfer of the z5DJo States of the Fe Atom

Abstract

Room-temperature thermal rate constants for quenching and energy transfer have been determined for the individual fine-structure levels of the z5DJo term of the Fe atom in collisions with He, Ar, and several molecular gases (N2, O2, H2, and CH4). The z5DJo term is the upper level of a transition at 372 nm which is convenient for laser fluorescence detection of the Fe atom. Emission profiles from all excited levels were observed to be exponential, and total removal rate constants were derived. The rate constants for the molecular gases were significantly larger [in the range of (3−8) × 10-10 molecule-1 cm3 s-1] than for the inert gases [(0.3−1.3) × 10-10 molecule-1 cm3 s-1]. No evidence for collisional transfer to the neighboring b3H and a3D states was found, and upper limits for the collisional transfer rate constants are reported. Rate constants for intramultiplet transfer within the z5DJo state were determined for He and O2. The intramultiplet rate constants for He summed over all final fine-structure levels roughly equaled the total removal rate constants, while they were ∼10% of the total removal constants for O2.