Exploration for electronic transitions and photodissociation mechanism of hydrogen iodide

Abstract

The electronic transitions and excited-state fragmentation of hydrogen iodide have been studied within the A-band continuum. The extinction intensity for the excitations from the ground to the low-lying electronic states are derived by performing the wave packet simulations of nuclear dynamics in this study. The quantum yields of the spin-excited I*\({(^{2}P_{1/2})}\) product at the different photon energies are determined as well. The results suggest that the possibility of intersystem crossing can be neglected. Employing the time-dependent density functional theory (TDDFT), the four highest occupied and the two lowest unoccupied orbitals of hydrogen iodide have been analyzed, and the transition to the \({A^{1}\Pi_{1}}\) state is found to be most probable in the first absorption band.