Extraction of resonances via wave packet propagation in Chebyshev order domain: collinear H + H2 scattering

We show that resonance positions can be determined by propagating a wave packet in the order domain of the Chebyshev operator. The Hermitian Hamiltonian is used in the Chebyshev propagation so that the instability associated with a complex Chebyshev operator is avoided. The outgoing boundary conditions are imposed in a window function in the Chebyshev order domain, which allows accurate determination of the resonance positions. A numerical example is given for the collinear scattering of H + H2. The relationship of the present approach with existing methods is also explored.