Fig. 6.

The growth with chain length (for all-trans alkanes) in the number of significant three-center integrals, 〈K|μν〉_g, for three different metrics. We used ω = 0.1 a.u for the attenuated Coulomb metric. The calculations used the pvdz basis and its corresponding auxiliary basis. Significant integrals are those whose magnitude exceeds a drop tolerance. Results are plotted for two different drop tolerances: 10^–6 (Left) and 10^–9 (Right). Quadratic growth is evident in the Coulomb metric, whereas the other metrics show onset of linear growth.