The Calculated Dielectric Function and Optical Properties of Bimetallic Alloy Nanoparticles

Bimetallic alloy nanoparticles have been recently studied widely due to their important applications in various areas including catalysis, medical, and optical devices. However, it remains a challenge to elucidate and predict their optical properties theoretically due to the lack of dielectric permittivity of the alloys. Here, we propose a general method for calculating the optical properties of bimetallic alloy nanoparticles based on the classical Drude–Lorentz–Sommerfeld model. The bowing rule is used by introducing a quadratic polynomial to deal with the problem of how the electron number, the effective mass, the energy, and the like are bowed after alloying. The strategy of probability allocation is applied to estimate the bound oscillator strength of the alloy material. This method is effective and general and can find important applications in predicting the dielectric function and optical properties of bimetallic alloy nanoparticles.