Photodissociation dynamics of methacrylonitrile (H 2 CdC(CH 3 )CN) and 2-butenenitrile at 193 nm have been investigated by measuring laser induced fluorescence spectra of CN fragments. From the spectra, internal and translational energy distributions of CN have been obtained. For both molecules, the measured energy distributions are well represented by statistical prior calculations, assuming the CN and allyl radical products rather than the propenyl isomer. Ab initio calculations were performed for the relevant product species and transition states for isomerization and CN elimination. It has been concluded that methacrylonitrile dissociates in the ground electronic state via allyl cyanide formed by CN and H atom migration prior to dissociation. The quantum yield of the CN channel from methacrylonitrile was measured to be 0.012 ( 0.001.

The photodissociation dynamics of formic acid (HCOOH) at 206 nm have been investigated from rotationally resolved laser induced fluorescence spectra of OH (2 Π) fragments produced exclusively in the ground state. From the spectra, the rotational energy of the fragments was measured to be 820 ± 50 cm −1. The translational energy released in the products, which is 87% of the total available energy of the system, was also measured from analyses of the Doppler profiles. Joining these data with quantum chemical molecular orbital calculations, we have concluded that the dissociation should take place along the S1 surface with an exit channel barrier and also that the energy partitioning is determined at the exit channel.

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The photodissociation dynamics of tert-butyl hydroperoxide at 193 nm was investigated by measuring rotationally resolved laser-induced fluorescence spectra of OH fragments. The OH fragments are exclusively produced in the X( 2 Π 1/2,3/2 ) state. From the spectra, the fraction of the available energy distributed among the products was found to be f r (OH) ) 0.04, f t ) 0.56, f int (t-BuO) ) 0.40, with negligible fraction of OH being in excited vibrational states. In addition, vector correlations were obtained by analyzing the Doppler profiles of the spectra. The detailed dynamics of the dissociation process is discussed compared to the dissociation of H 2 O 2 .

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