Channel-dependent complex absorbing potential for multi-channel scattering

An early study (J. Chem. Phys. 108 (1998) 1429) showed that the use of complex absorbing potential (CAP) can significantly reduce the reflection of wavefunction from the absorbing boundary over the standard negative imaginary potential, especially at low kinetic energies. In the present work, we further extend the use of CAP to multi-channel scattering by employing channel-dependent CAPs. Each of these CAPs is optimized for a specific open channel using an efficient time-independent propagation approach. Application to the prototype inelastic scattering of He+H2 demonstrated the accuracy and efficiency of the channel-dependent CAP for extracting state-to-state scattering information.