TABLE V.

Errors of direct summation potentials for Gaussian potentials between two H atoms at different PME setups. These values are the difference between two error functions, erf(βR_c) − erf(β₀R_c). Here, R_c is the direct summation cutoff distance, and $\beta =1/\left(0.7147597\cdot \sqrt{2}\right){\text{Å}}^{-1}$ for the H atom pairs.

Cutoff distance (Å)	7	8	9	10	11
β0 = 0.3 Å−1	3.0 × 10−3	6.9 × 10−4	1.3 × 10−4	2.2 × 10−5	3.1 × 10−6
β0 = 0.4 Å−1	7.5 × 10−5	6.0 × 10−6	3.6 × 10−7	1.5 × 10−8	4.9 × 10−10
β0 = 0.5 Å−1	7.4 × 10−7	1.5 × 10−8	2.0 × 10−10	1.5 × 10−12	7.3 × 10−15