Figure 12: The calculated optical conductivity.
Reflectivity
Portion of the electromagnetic radiations that bounces back from surface of a material can be envisaged by using the reflectivity relation which is expressed as:
\begin{equation} \text{R\ }\left(\omega\right)\ =\ \ \ \ \ \left|\frac{\sqrt{\varepsilon\left(\omega\right)}\ \ -1}{\sqrt{\varepsilon\left(\omega\right)}+1}\right|^{2}\nonumber \\ \end{equation}
From figure 13, static value of the reflectivity R(0) is 0.05. It increases slowly upto 5 eV, but then upsurges gradually and attains its maximum value of 0.89 at photonic energy of 12.9 eV. It is observed that the reflectivity is maximum in the energy region where absorption was found to reveal decreasing trend.