A numerical test of different integral conditioning approximations for a semiclassical initial value representation for wavepacket propagation

Recent numerical evidence indicates that the rapid spreading of nearby classical trajectories in chaotic regions results in numerical difficulties and reduced accuracy for semiclassical initial value representation methods. These problems can be significantly reduced and the accuracy of the methods increased through the application of integral conditioning techniques, which have been developed for the numerical evaluation of integrals with highly oscillatory integrands. This work studies the effectiveness of these conditioning techniques, when applied to one semiclassical initial value representation wavepacket propagation procedure, the HK propagator method. (C) 1998 Elsevier Science B.V.