Fig. 5.

Total energy of the water dimer as the distance coordinate changes. The translated energy is defined as $E_{\text{Total}}^{\text{translated}}(s_j)=E_{\text{Total}}(s_j)-{\overline{E}}_{\text{Total}},$ where j = 1, 2, …, M. This translation centres the resultant mean energy so that it becomes 0 kJ mol⁻¹. Barrier 1 (left) consists of four data points, while barrier 2 (right) consists of seven data points (as the energy minimum data point is shared by both barriers)