Prior to production, the pure-liquid systems were subject to energy minimization with harmonic bonds (scaling of the force constant with s as k b (s) = s -2 k * b ), followed by a minimization with rigid bonds, and by 0.1 ns equilibration. Simulations without correction potentials were carried out for 10 ns, and the coordinates were written out every 100 steps. In spherical geometry, the oxygen atom of one reference water molecule was restrained to the center of the box with a harmonic force constant of 10 4 kJ mol -1 nm -2 .