Jai P Mittal
Articles written in Journal of Chemical Sciences
Volume 106 Issue 6 November 1994 pp 1307-1314
Infrared diode laser probing of methane in excimer laser photolysis of pyruvic acid
Sisir K Sarkar Jai P Mittal George W Flynn
The photodissociation of pyruvic acid at 193 nm has been studied and one of the photoproducts, methane, was detected using an infrared diode laser absorption probe technique. Using second-derivative absorption spectroscopy at 1346.326 cm-1[
Volume 113 Issue 4 August 2001 pp 333-342
TEA CO2 laser-induced reaction of CH3NO2 with CF2HCl: A mechanistic study
Rajesh K Vatsa Sisir K Sarkar Jai P Mittal
Dissociation of nitromethane has been observed when a mixture of CF2HCl and CH3NO2 is irradiated using pulsed TEA CO2 laser at 9R (24) line (1081 cm-1), which is strongly absorbed by CF2HCl but not by CH3NO2. Under low laser fluence conditions, only nitromethane dissociates, whereas at high fluence CF2HCl also undergoes dissociation, showing that dissociation occurs via the vibrational energy transfer processes from the TEA CO2 laser-excited CF2HCl to CH3NO2. Time-resolved infrared fluorescence from vibrationally excited CF2HCl and CH3NO2 molecules as well as UV absorption of CF2 radicals are carried out to elucidate the dynamics of excitation/dissociation and the chemical reactions of the dissociation products.
Volume 119 Issue 4 July 2007 pp 277-282
Almuth Laeuter Hans-Robert Volpp Jai P Mittal Rajesh K Vatsa
The collision-free, room temperature gas-phase photodissociation dynamics of CH3CFCl2 (HCFC-141b) was studied using Lyman-𝛼 laser radiation (121.6 nm) by the laser photolysis/laserinduced fluorescence `pump/probe’ technique. Lyman-𝛼 radiation was used both to photodissociate the parent molecule and to detect the nascent H atom products via ($2p^2$P → $1s^2$S) laser-induced fluorescence. Absolute H atom quantum yield, $\phi_H = (0.39 \pm 0.09)$ was determined by calibration method in which CH4 photolysis at 121.6 nm was used as a reference source of well-defined H atom concentrations. The line shapes of the measured H atom Doppler profiles indicate a Gaussian velocity distribution suggesting the presence of indirect H atom formation pathways in the Lyman-𝛼 photodissociation of CH3CFCl2. The average kinetic energy of H atoms calculated from Doppler profiles was found to be $E_{\text{T(lab)}} = (50 \pm 3)$ kJ/mol. The nearly statistical translational energy together with the observed Maxwell-Boltzmann velocity distribution indicates that for CH3CFCl2 the H atom forming dissociation process comes closer to the statistical limit.
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