Photodissociation of HI and DI: Testing models for electronic structure via polarization of Atomic Photofragments

Abstract

The photodissociation dynamics of HI and DI are examined using time-dependent wavepacket techniques. The orientation and alignment parameters, a_Q^(K)(p), are determined as a function of photolysis energy, for the resulting ground state I(²P_3/2) and excited state I(²P_1/2) atoms. The a_Q^(K)(p) parameters describe the coherent and incoherent contributions to the angular momentum distributions from the i A¹Pi₁, a³Pi₁, and t³Sigma₁ electronic states accessed by perpendicular excitation and the a³Pi_0⁺ state accessed by a parallel transition. The outcomes of the dynamics based on both shifted ab initio results and three empirical models for the potential energy curves and transition dipole moments are compared and contrasted. It is demonstrated that experimental measurement of the a_Q^(K)(p) parameters for excitation from the vibrational ground state, v=0, would be able to distinguish between the available models for the HI potential energy curves and transition dipole moments. The differences between the a_Q^(K)(p) parameters for excitation from v=0 stands in sharp contrast to the scalar properties, i.e., total cross section and I^* branching fraction, which require experimental measurement of photodissociation from excited vibrational states, v>0, to distinguish between models.

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