On the contribution of non-additive three-body interactions to the third virial coefficient of para-hydrogen

We use a path-integral Monte Carlo method together with state-of-the-art pair and three-body potentials to calculate the third virial coefficient C ( T ) of para-hydrogen in the temperature range 30–2000 K. Our results point out that non-additive three-body interactions have a sizable effect in determining the value of C ( T ) for T < 200 K. Although a good agreement with experimental data is obtained, the accuracy of the calculations is limited by the incomplete knowledge of the three-body potential energy surface.