Comparison of density-functional, tight-binding, and empirical methods for the simulation of amorphous carbon

摘要: Amorphous carbon networks are used to test various levels of theoretical approaches molecular dynamics simulations. The density-functional theory as implemented in the Car-Parrinello method, nonorthogonal tight-binding environment-dependent interaction potential (EDIP), and Brenner compared directly liquid quench simulations containing 125 atoms at four densities. We find that low densities predictions agreement with those from theory, while structures produced by method compare well all does, however, a slightly lower ${\mathrm{sp}}^{3}$ fraction high presence singly coordinated frequency three-membered rings underpredicted EDIP methods due an overestimate strain energy relative density- functional experiment. Aside small rings, slight underestimate highest densities, very good theory. is also quantify statistical variability quenching, comparisons film growth verify quenching representation bulk amorphous carbon.