Abstract
We present a moving-boundary truncated-grid approach for integrating the time-dependent Schr & ouml;dinger equation in collinear triatomic reactive scattering (H + H2, F + H2). The grid is pruned by density and gradient criteria, boundary values are extrapolated in the logarithmic amplitude, and propagation proceeds on a compact, time-varying set. Relative to full-grid baselines, this method delivers smooth, small relative-L2 errors, preserves transmission probabilities and significant interference features, and uses far fewer grid points, achieving up to 1.56-fold shorter wall time. The comparisons with the FG benchmarks in the state-specific energy-resolved probabilities further accentuate the excellent performance of our TG method for practical applications. Computational results demonstrate that this method provides accurate and economical wave packet propagation for reactive scattering.