QUANTUM REARRANGEMENT SCATTERING CALCULATIONS USING THE INVARIANT IMBEDDING METHOD

We derive an algorithm to calculate quantum transmission and reflectio n amplitudes (S-matrix elements) for rearrangement reactions using the invariant imbedding method. Our approach can incorporate closed chann els, treat complex potentials (to simulate decay), and can be used wit hin an adiabatic representation (in which derivative coupling terms ar e present) or within a diabatic representation. The method can also be used to determine bound-state energies when only closed channels are present. The method is demonstrated on a rearrangement problem with tw o coupled potential surfaces (four channels) as a function of energy i n the energy region from the lowest channel threshold through the high est channel threshold.