NEWTONIAN PROPAGATION METHODS APPLIED TO THE PHOTODISSOCIATION DYNAMICS OF I-3(-)

A uniformly convergent propagation scheme designed for non-Hermitian H amiltonian operators is presented. The method is based on a Newtonian interpolation polynomial which is created by a recursive application o f the Hamiltonian operator on an initial wave function. The interpolat ion points used to construct the Newtonian polynomial are located in t he complex eigenvalue space of the Hamiltonian. A new algorithm is dev eloped to construct the interpolation points. Both time dependent and time independent quantities can be obtained using the same polynomial expansion. The method is particularly useful when negative imaginary p otentials are used. The photodissociation dynamics of I-3(-) is studie d as an example of the utility of the scheme to gain insight on a dyna mical encounter. The bond cleavage is followed in time simultaneously with the calculation of the Raman spectra. The study addresses the rol e of vibrational excitation of the reactant I-3(-) on the nascent I-2( -) spectral modulations and Raman spectra. (C) 1995 American institute of Physics.