Isochoric heat capacity and cluster structure of simple liquid

The formation process of the short-range order and the liquid itself in the critical region is described in terms of a cluster model. The “exploding” formation of dimeric clusters marks the onset. The estimation of cluster size on a vapor–liquid equilibrium curve is proposed. The X-ray diffraction analysis for argon on the saturation line and the observed correlation between the temperature dependences of number of particles in the cluster and the isochoric heat capacity of simple liquids validate the model.