Photodissociation Dynamics of 1,3-Butadiene at 157 nm

Photodissociation of 1,3-butadiene at 157 nm has been investigated using the photofragment translational spectroscopy technique. Tunable VUV synchrotron radiation was used for product photoionization detection. Six dissociation channels have been identified including C4H5 + H, C4H4 + H2, C3H3 + CH3, C2H3 + C2H3, C2H4 + C2H2, and C4H4 + H + H. The product kinetic energy distributions for all observed dissociation channels have been determined. The relative branching ratios for different channels are also estimated. It appears that the majority of the excited 1,3-butadiene molecules go through isomerization before they dissociate, while direct bond dissociation channels are less important in comparison with 1,2-butadiene photodissociation at the same excitation wavelength.