Schematic diagram of the photodissociation of triplet acetaldehyde to and HCO. represents the excitation energy, is the electronic energy barrier for the forward dissociation reaction, is the electronic energy barrier for the reverse, association reaction, is the electronic dissociation energy, is the excess energy at the transition state, and is the total available energy to the and HCO products. The inset is the transition state structure for the photodissociation of triplet acetaldehyde, as calculated at .
Approximations to the minimum-energy path profiles for the dissociation of acetaldehyde, using UB3LYP/cc-pVTZ optimized geometries.
Vibrational energy distributions for HCO and calculated for five different excess energies (labeled in ). The data and labels for the highest and lowest excess energies are shown in bold. The energy of the lowest vibrational levels in HCO and , the HCO bend at (Ref. 94), and umbrella mode ( or ) (Ref. 95), respectively, are indicated by arrows.
Rotational energy distributions for HCO and calculated for the labeled five different excess energies. The distributions for the highest and lowest are shown in bold. The distributions change from symmetric “Gaussian shaped” at low energy to more asymmetric “Boltzmann shaped” at higher energy.
Total translational energy distributions calculated for five different excess energies (labeled in ). The data and labels for the highest and lowest excess energies are shown in bold. The energy of the exit channel is shown as an arrow and indicates that most of the exit channel energy is partitioned into translational energy.
Natural log of the HCO population as a function of HCO rotational energy for three different excess energies (labeled in ). The top panel shows the classical trajectory results and the lower panel shows experimental results, taken from Ref. 46.
Amount of average energy partitioned into internal and external degrees of freedom of HCO and as a function of excess energy . The average energy has been separated in an impulsive reservoir, which is determined by the fixed exit channel [panel (a)], and statistical reservoirs [panel (b)] that increase with increasing excess energy (see text).
Vibrationless relative energies with respect to the equilibrium structure, for the forward and reverse energy barriers, and , respectively, and the dissociation energy for the photodissociation of triplet acetaldehyde. See text and Fig. 1 for definition of energetics.
Energy partitioning amongst rotational, , vibrational, , and relative translational, , degrees of freedom for photoproducts initiated with energy at the transition state and with energy at the product configuration.
Experimental energy partitioning amongst rotational, vibrational, and relative translational degrees of freedom for photoproducts. The values of are as reported in the original work, while assumes a exit channel barrier.
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