Experimental and Theoretical Kinetics for the Reaction of Al with O₂ at Temperatures between 23 and 295 K

Abstract

The first study of the kinetics of Al atoms with O2 at low and ultralow temperatures is reported. Rate constants have been measured from 295 to 23 K using the pulsed laser photolysis−laser-induced fluorescence (PLP-LIF) technique in a CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme) apparatus. Rate constants were found to increase monotonically with decreasing temperature: k(T) = (1.75 ± 0.10) × 10-10(T/298)-0.25±0.02 exp[(7.3 ± 3.0)/T] cm3 s-1. The rate constant for the reaction Al with O2 has also been calculated as a function of temperature using a theoretical approach based on the adiabatic capture centrifugal sudden approximation (ACCSA) method. These calculations were found to be in good agreement with experimental results and were able to explain the observed temperature dependence by the open-shell nature of the reactants. Possible astrophysical implications are also discussed concerning the chemistry of aluminum atoms in the interstellar medium.

The Si($^\mathsf3$PJ) + O$_\mathsf2$ reaction: A fast source of SiO at very low temperature; CRESU measurements and interstellar consequences

“…In our experiment, the possibility of partial photolysis of the reactant gas O 2 due to laser focusing was examined. We returned to a previous study involving reactions of aluminum atoms with molecular oxygen (Le Picard et al 1997). In this experiment, no focusing of the photolysis laser was required to produce aluminum atoms from the precursor Al(CH 3 ) 3 .…”

“…Although this study was carried out at a slightly higher temperature ( The aim of the present work was therefore to answer the request of Pineau des by studying the kinetics of the Si( 3 P) + O 2 → SiO + O reaction in the temperature range 15-300 K. This work was carried out at the University of Rennes I using the CRESU facility associated to the PLP-LIF technique (Pulsed Laser Photolysis -Laser Induced Fluorescence). In recent years, experiments using this technique, in close collaboration between our laboratory at Rennes and Prof. Ian Smith's laboratory at Birmingham, allowed us to measure the rate coefficients for many rapid neutral reactions at extremely low temperature involving radicals CN, OH, CH, C 2 H (Smith & Rowe and references therein 2000), and atoms, Al( 2 P) (Le Picard et al 1997) and C( 3 P) (Chastaing et al 2000(Chastaing et al , 2001.…”

Uniform Supersonic Chemical Reactors: 30 Years of Astrochemical History and Future Challenges

“…O( 3 P) 39 [44] OH 56 [45] CN 56 [46] CH 56 [47] 1 C 2 ( 1 S g + )57 [48] C 2 N(X 2 P i )54 [49] O 2 13 [11,43] 13 [50] 15 [51] 145 [52] 15 [53] 23 [54] 15 [55] 24 [56] NO 13 [50] 53 [57] 24 [52] 24 [52] 15 [53b, c] 15 [55b] 48 [58] H 2 50 [59] 6 [9] 11 [ 23 [66] 53 [57] 24 [67] 200 [68] 23 [69] C 2 H 2 25 [70] 23 [66] 53 [57] 15 [51a, c, 71] 24 [67,72] 24 [73] 39 [68a, 74] 15 [53a, 75] 15 [76] 23 [77] 23 [69] C 2 H 4 25 [70] 23 [66] 53 [57] 15 [51a, 78] 24 [67] 24 [73] 39 [68a, 74] 15 [53a] 15 …”

Reaction dynamics of Al+O2→AlO+O studied by the crossed-beam laser-induced fluorescence technique

“…The exothermic reaction ͑1͒, which is the only possible pathway under single collision conditions, has a large rate constant at room temperature, and a negative temperature dependence of the rate constant has been reported. 11 The dynamics of this reaction has also been studied from experimental [12][13][14][15][16][17] and theoretical viewpoints. 18 -20 However, only little information has been available for the potential energy surface of this reaction until the recent multiconfigurational study carried out by Pak and Gordon.…”