Towards an Optimal Parametrization of a Transferable Tight-Binding Model for Carbon-Hydrogen Compounds

We develop a method and a computer code for the systematic optimization of a transferable tight-binding model for carbon-hydrogen compounds. We take as reference a density-functional theory calculation in the local density approximation and, using a «downhill simplex» routine, we minimize the squared difference between the energies predicted by the reference model and those obtained with our tight-binding approach. With the resulting best-fit parameters our tight-binding model improves significantly its accuracy and predictiveness for the calculation of the total adiabatic potential energy and the band structure of arbitrary carbon-hydrogen compounds. Additionally, a serious unphysical behavior exhibited by the original parametrization has been corrected. Advisor: Prof. Nicola Manini Co-Advisor: Prof. Giovanni Onida