Crystallization via shaking in a granular gas with van der Waals interactions

We investigate the effect of van der Waals forces on a collection of granular particles by means of molecular dynamics simulations of a vibrated system in three dimensions. The van der Waals interactions introduce two phase coexistences: one between a random close packing and a gas and a second between a polycrystalline dense state and a gas, where the dense, disordered component crystallizes when the driving amplitude exceeds a threshold value. The region of stability of the ordered state in the nonequilibrium phase diagram grows in size as the Hamaker constant increases or the degree of dissipation increases.