Physical Sciences and Mathematics Commons^™

A lattice model of the atom is used to study the excitonic transition in dense fluids. With the use of a simple Hamiltonian for both atomic and interatomic interactions, simulations were made by allowing nuclei to move and by using hard-sphere configurations for the nuclei. The hard-sphere simulations are compared with several analytical theories. Rehybridization of atomic orbitals is found to occur in the hard-sphere systems, while clustering is present in the full simulations.

Liquids that involve changes in electronic structure are difficult to simulate using pairwise additive forces. In this paper we use a semiempirical model of the internal structure of atoms in order to simulate simultaneously electronic and nuclear dynamics of fluids. The proposed excitonic phase of mercury is critically examined with these models.