Comparison of Blaugrund and Monte Carlo centroid-shift calculations

A comparison of Blaugrund and Monte Carlo centroid-shift calculations is presented. We find that the two methods of calculation agree to within 15% if the lifetime is greater than several times the flight time between collisions. The differences are systematic and hence predictable. These discrepancies depend only weakly on the reduced energy parameter epsilon and are a function of the mass ratio only when the projectile-target mass ratio is close to unity. Furthermore, the discrepancies between these methods of calculation only show a weak dependence on the choice of atomic interaction potential. On the other hand, for lifetimes that are shorter than a few times the flight time between collisions, the situation is more complex. (orig.)