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Abstract
Quantitative understanding of the chemical speciation and thermodynamics of metal-carbon polymerizations within three different liquid metals, Al, Cu, and Ag, will enable new classes of high-performance materials. Metalocarbons, low molecular weight metal-carbon species, are identified using ab initio molecular dynamics (AIMD) by monitoring the long-time evolution of thermodynamically favored species within explicit metal atom solvent. Metalocarbons observed in AIMD agree with the structures determined by ab initio molecular mechanics and statistical thermodynamics from a density functional theory implementation of a conductor-like state model (COSMO) of solvation. The metalocarbon Gibbs energies calculated from the implicit COSMO solvation agree quantitatively with the Gibbs energy long-time averages computed by AIMD. Thermochemical analysis predicts that metalographene structures are thermodynamically more stable than smaller metalocarbon species, suggesting that metalocarbons form metalographenes in liquid aluminum, copper, and silver solutions. I identify the influence of charge and electric potential on the metal solution reaction mechanism. Redox reactions affect the step addition equilibrium constants. COSMO and AIMD predict aluminum-carbon vibrational spectra from inelastic neutron scattering (INS) within liquid metal and solid metal compositions. An experimental inelastic neutron scattering vibrational spectrum of an aluminum covetic with 3 wt% carbon matches specific metalographenes. This novel finding provides a unique avenue for identifying different metalographene compositions within aluminum covetics and may become an important tool to develop high performance materials in many different metals.
