Thermal Kinetics of Aln– + O2 (n = 2–30): Measurable Reactivity of Al13–
journal contributionposted on 28.06.2019, 00:00 by Brendan C. Sweeny, Shaun G. Ard, Albert A. Viggiano, Jordan C. Sawyer, David C. McDonald II, Nicholas S. Shuman
Mass-selected aluminum anion clusters, Aln–, were reacted with O2. Rate constants (300 K) for 2 < n < 30 and product branching fractions for 2 < n < 17 are reported. Reactivity is strongly anticorrelated to Aln– electron binding energy (EBE). Al13– reacts more slowly than predicted by EBE but notably is not inert, reacting at a measurable 0.05% efficiency (2.5 ± 1.5 × 10–13 cm3 s–1). Al6– is also an outlier, reacting more slowly than expected after accounting for other factors, suggesting that high symmetry increases stability. Implications of observed Al13– reactivity, contributions of both electronic shell-closing and geometric homogeneity to Aln– resistance to O2 etching, and future directions to more fully unravel the reaction mechanisms are discussed.