Shock tube study of the reactions of the hydroxyl radical with combustion species and pollutants. Final report

Shock heating t-butyl hydroperoxide behind a reflected shock wave has proved to be as a convenient source of hydroxyl radicals at temperatures near 1000 K. We applied this technique to the measurement of reaction rate coefficients of OH with several species of interest in combustion chemistry, and developed a thermochemical kinetics/transition state theory (TK-TST) model for predicting the temperature dependence of OH rate coefficients

Collisionally induced optical double resonance in I2 : rotational analysis of the D'(2g) - A'(2u) laser transition

The I2 D'(2g)-A'(2u) transition has been excited by collisionally induced optical double resonance. This system has been rotationally analysed for more than 50 vibrational levels of the A'(2u) state. The long range behaviour of the A' state has been studied. The dissociation energy of this state has been determined to be Dc = 2 505.7 ± 1.9 cm-1. The D' state has been identifed with the α state of King et al. (Chem. Phys. 56 (1981) 145). The energies of the D' and A' states have been determined relative to X 1∑g+(ν = 0, J = 0) to be T0 = 40 331.6 ± 1.6 cm-1 and To = 9 988.7 ± 1.6 cm-1, respectively. The mechanism of this double resonance is discussed. Efficient collisional transfer to the D' state is observed and helps to shed some light on the operation of the optically pumped I2 D'-A' laser.La transition D'(2g)-A'(2u) de la molécule I2 a été excitée par double résonance optique induite par collisions. Une analyse rotationnelle correspondant à plus de 50 niveaux vibrationnels de l'état A'(2u) a été effectuée. On a étudié le comportement de l'état A' à longue distance internucléaire. L'énergie de dissociation de cet état a été déterminée : De = 2 505,7 ± 1,9 cm-1. On a montré que l'état D' est l'état α de King et al. (Chem. Phys. 56 (1981) 145). Les énergies de D' et A' relatives à l'état fondamental X 1∑g+(ν = 0, J = 0) ont été déterminées comme étant T0 = 40 331,6 ± 1,6 cm -1 et T0 = 9 988,7 ± 1,6 cm-1 respectivement. On discute le mécanisme de la double résonance. Un transfert collisionnel de grande efficacité vers l'état D' a été observé, ce qui permet de mieux comprendre le fonctionnement du laser à iode D'-A' pompé optiquement

HYPERFINE STRUCTURE IN THE B3Π+Ou STATE OF I2 CLOSE TO THE DISSOCIATION LIMIT

International audienceThe excitation spectrum of a supersonic beam of I2 is explored at ∼ 1 MHz resolution for vibrational levels (υ′−75−81) close to the dissociation limit of the B3Π+Ou state (499.5-500.0 nm). The hyperfine structure is analysed and shows the expected theoretical trend. The analysis of perturbed lines is now in progress in order to localise the potential curves of these previously unobserved perturbing states sharing the same dissociation limit as B3Π+Ou

EMISSION SPECTRA FROM THE CHEMICAL REACTION OF HEATED Cu WITH METASTABLE OXYGEN AND Cl2, COMPARISON WITH LASER INDUCED FLUORESCENCE AND ABSORPTION SPECTRA OF CuCl2

We present the results of a spectroscopic investigation of CuCl2 vapour obtained from laser induced fluorescence recorded by Fourier transform spectrometry, and give preliminary spectroscopic constants for the [MATH] and [MATH] states of Cu35Cl2. Coupled with data obtained from absorption experiments on CuCl2, this work brings us closer to understanding the mechanism of the reaction of copper with chlorine in the presence of singlet oxygen ([MATH]), which is accompanied by an intense red flame. This emission has been proposed as a possible candidate for the production of a visible or infrared chemical laser. We consider this question in view of lifetime measurements on the [MATH] state of the CuCl2 molecule, now accepted to be the emitting species, and also compare the infrared and visible spectra of CuCl2 with the chemiluminescence recorded around 1.2 and 0.7 µm