Ewald sum adjustment

I followed the recipe given in http://www.dl.ac.uk/TCS/Software/DL_POLY/FAQ2.html with $\mbox{cutoff}=7.9$ and found $\alpha=0.42,k_1=k_2=k_3=6$.

I also checked that the relation $E_{coul}=-V_{coul}$ is verified along the whole simulation.