<div dir="ltr"><span style="font-size:16px;background-color:rgb(245,245,245)"><span style="font-size:12.8px;background-color:rgb(255,255,255)">Dear Wien Users ,</span><br>how to determine</span><span style="font-size:16px;background-color:rgb(245,245,245)"> </span><span style="font-size:16px;background-color:rgb(245,245,245)">optical gap</span><span style="font-size:16px;background-color:rgb(245,245,245)"> </span><span style="font-size:16px;background-color:rgb(245,245,245)">from</span><span style="font-size:16px;background-color:rgb(245,245,245)"> </span><span style="font-size:16px;background-color:rgb(245,245,245)">the graph of </span><span style="font-size:16px;background-color:rgb(245,245,245)"> </span><span style="font-size:16px;background-color:rgb(245,245,245)">optical</span><span style="font-size:16px;background-color:rgb(245,245,245)"> </span><span style="font-size:16px;background-color:rgb(245,245,245)">properties</span><span style="font-size:16px;background-color:rgb(245,245,245)"> ? is determine from the graph of </span><span style="font-size:16px">absorption coefficient? and how ?</span><br></div>