Three Photon absorption spectroscopy:
(3+1)REMPI of HCl (I1D2 - X1S+)

Huasheng Wang and Ágúst Kvaran*
Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavík, Iceland


 Improved spectroscopic parameters for the I1D2 Rydberg state and rotational population in the ground state of HCl are derived from simulation analysis of the (3+1)REMPI specrum. The superiority of using the (3+1)REMPI spectrum of HCl in the excitation region 88200 - 88900 cm-1 for spectroscopic and dynamic purposes are demonstrated.  The mechanism of the three photon excitation in the I1D2 - X1S+ transition is discussed.