UV Photodissociation of Acetylene in Various Environments

In the present experiment the photodissociation of H atoms from acetylene by 193nm photon is studied using photofragment ion imaging. First the results on photodissociation of isolated acetylene molecules in the gas phase are presented in good agreement with previous studies using different techniques. Then new results are presented on the photodissociation of acetylene embedded in clusters. Our previous TOF study pointed out that the H fragment caging combined with multiphoton processes can yield fragments with significantly higher velocities in comparison to H atoms originating from photodissociation of isolated molecules. The high resolution of the present imaging experiment allowed partly resolving the vibrational structure of photodissociation precursors. Thus the dynamics of the photodissociation process in the clusters could be described in more detail.