This rejection condition is expected to speed up the calculation, since the energy calculation is avoided for the rejected sampling points. The energy calculation accounts for the largest portion of the CPU time spent in the surface sampling. For the structure KAXQIL 44 , the Lennard-Jones potential calculation represents up to 90% of the calculation time for 100,000 sampling points per sphere (with the initial algorithm). The higher the factor 𝜇, the more rejections there would be. But, if too many points are rejected, the accuracy would drop. Here again, we used a statistical analysis to determine the optimal value of 𝜇, making our sampling faster without compromising the accuracy of the enthalpy calculation. The results are displayed on Figure . unchanged, the optimal value is therefore 𝜇 ≃ 0.85, because it give the lowest computation time with a similar RMSE. We note that it would be possible, in specific cases, to explore higher values of 𝜇 that trade a bit more accuracy in exchange of further speed gains.