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[R^(-)(7) transition in v₄ band], the progress of the reaction was monitored. The quantum yield of formation of methane = 0.09 ± 0.01 and was further corroborated by a simple measurement of pressure changes following the photolysis. The secondary photolysis of the photoproduct acetaldehyde via the established route was found to be negligible. This result may help to account for the energetics of the photodissociation process by a 6.4 eV excimer laser photon. The possibility of using this technique to examine the nascent methane molecule in real-time domain to gain better insight of the dissociation dynamics is also indicated.

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.

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.