APPLICATION OF SYMPLECTIC INTEGRATOR TO STATIONARY REACTIVE-SCATTERING PROBLEMS - INHOMOGENEOUS SCHRODINGER-EQUATION APPROACH

The FFT-symplectic integrator (SI) scheme devised for solving the wave packet propagation problem is applied to stationary reactive-scatteri ng problems. In order to relate the stationary problem to the time-dep endent problem, a class of Schrodinger equation with an inhomogeneous wave source term is;introduced. By using the equivalence between the s tationary scattering eigenstate and the equilibrium state of the inhom ogeneous Schrodinger equation, the scattering eigenstates can be compu ted by integrating-the inhomogeneous Schrodinger equation;with the FFT -SI scheme, A Gaussian wave source is proposed as an efficient wave so urce exhibiting rapid relaxation toward the eigenstate. Our method is tested by a-one-dimensional example which has an analytical solution, and great numerical accuracy is confirmed. It is further examined by a n example of time-dependent scattering and by a two-dimensional exampl e of chaotic tunnel-scattering. (C) 1997 American Institute of Physics .