Kinetic study of the absolute rate constant for the reaction of Rb + O2 + N2 over the range 709–897 K by time-resolved atomic resonance absorption spectroscopy

✍ Scribed by David Husain; Bing Ji

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 556 KB
• Volume: 79
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(90)90148-k

✦ Synopsis

We present a kinetic study of the reaction Rb 4-O2 + Nz ~ RbO2 + N2 by time-resolved atomic resonance absorption spectroscopy. Rb(52Si/2) was generated by the pulsed irradiation of Rbl and RbCI vapors in equilibrium with their solids at elevated temperatures in the presence of 02 and N2. The atom was then monitored photoelectrically in the "single-shot mode" using the Rydberg transition at ~, = 420.2 nm (Rb(6p(2P3/2)) ~ Rb(5s(2St/2))) and atomic decay profiles were recorded and analyzed by computer.

Absolute third-order rate constants (k3) were measured across the limited temperature range 709-897 K by two different kinetic procedures to yield an average experimental value for a single temperature of 800 K, namely, k3(800K) = 2.24 x 10 -3° cm 6 molecule -2 s -I . The temperature dependence of the rate constant was calculated using a Troe extrapolation based on unimolecular rate theory for the reverse process of dissociation to yield a form that can be fired to the expression ln(k3/cm 6 molecule -2 s-i) = -0.217 [In(T/K)] 2 + 1.16 In(T/K) -66.3 for the range 200-2000 K. This result is compared with analogous rate data for the reactions among Li, Na, K +02 + N2.