From sticky hard spheres to Lennard-Jones potentials and many-body expansions for rare gas solids

Full text: The Lennard-Jones (LJ) potential is the most widely used interaction potential between atoms with widespread applications in physical, chemical and biological sciences. This simple potential also has the advantage that the cohesive energy, pressure and the bulk modulus of a simple solid (simple cubic, body-centered cubic, and face-centered cubic) can be expressed analytically as a function of volume using lattice sums in three dimensions, originally developed by Hund, Born and Lennard-Jones [1]. Changing the LJ parameter allows to study the limit towards sticky hard spheres extensively used in nucleation theory [2]. By doing this, we can show for the first time an exponential increase in the number of minima with number of atoms in a cluster. Moreover, through many-body expansions using computer intensive relativistic coupled cluster methods we can get the cohesive energy for solid argon accurate to within 1 J/mol and within experimental accuracy [3]. This allows for the accurate simulation of melting of the rare gas solids with an accuracy of a few Kelvin [4], and to predict that the heaviest element in the periodic table, the rare gas element oganesson, is indeed rare but not a gas. (author)