Brus equation emission energy Δ"E" = "hc"/λ, where c is the speed of light). This is useful for calculating the radius of a quantum dot from experimentally determined parameters. The overall equation is "E", "m"*, and "m"* are unique for each nanocrystal composition. For example, with CdSe nanocrystals: Brus equation The Brus equation can be used to describe the emission energy of quantum dot semiconductor nanocrystals (such as CdSe nanocrystals) in terms of the band gap energy "E", Planck's constant "h", the radius of the quantum dot "r", as well as the effective mass of the excited electron "m"* and of the
Williams–Landel–Ferry equation to temperatures at or above T only; the constants are positive and represent Arrhenius behavior. Extrapolation to temperatures below T is erroneous. When the constants are obtained with data at temperatures below T, negative values of C, C are obtained, which are not applicable above T and do not represent Arrhenius behavior. Therefore, the constants obtained above T are not useful for predicting the response of the polymer for structural applications, which necessarily must operate at temperatures below T. The WLF equation is a consequence of time–temperature superposition (TTSP), which mathematically is an application of Boltzmann's superposition principle. It is