Chemical stability and surface stoichiometry of vanadium oxide phases studied by reactive molecular dynamics simulations

摘要

Compositional stability of various vanadium oxides and oxide growth on vanadium surfaces have been stud ied using reactive molecular dynamics simulation methods. Vanadium dioxide (VO_2), sesquioxide (V_2O_3), pentoxide (V_2O_5), and hexavanadium tridecaoxide (V_6O_(13)) are studied in bulk crystalline and thin film struc tures, investigating charge distribution and pair distribution functions of particle interactions. The stability is estimated to be pentoxide, hexavanadium tridecaoxide, sesquioxide, and dioxide respectively in decreasing order in thin film structures. We then analyze oxide growth kinetics on vanadium (100) and (110) surfaces. The oxidation rate, stoichiometry, charge distribution, and the effect of surface orientation on kinetic phe nomena are noted. In the early stages of surface oxidation of our simulation configurations, sesquioxide is found to be the dominant component. The modeling and simulation results are compared with experiments where available.