Insights into 2-Chloropyrimidine fragmentation through a thermochemical analysis of the ionic fragments

In the present work we have studied the photoinduced ion chemistry of the 2Cl-pyrimidine molecule in the energy region 9-14 eV. The theoretical gas phase enthalpies of formation of the main fragments calculated using the G3B3 and G2 ab initio methods are compared to the experimental values, derived by the measured appearance energy of the fragments. This approach provides new insights into both the geometric structure of the ionic fragments and the basic mechanisms governing the molecular fragmentation.