  Previously a compact formula for total reaction cross section for heavy-ion
collisions as a function of energy was obtained by treating the angular
momentum $l$ as a continuous variable. The accuracy of the continuum
approximation is assessed and corrections are evaluated. The accuracy of the
compact equation can be improved by a simple modification, if a higher accuracy
is required. Simple rules to determine the barrier heights and the penetration
probability for the $l$ partial wave from experimental data are presented, for
the collision of identical or non-identical light nuclei.
