Converting UV-Vis Diffuse Reflectance Spectroscopy (DRS) data to absorbance requires a few steps. Here's a general procedure to follow:

It's important to note that this is a general procedure, and the specific details may vary depending on the instrument and software used for data analysis. Some UV-Vis spectrophotometers may have dedicated software that can perform these calculations automatically. Consulting the instrument manual or software guide can provide more specific instructions tailored to your setup.

By default UV-Vis DRS provides wavelength vs percentage of reflectance data. During characterization it is possible to transformed the reflectance to absorbance automatically using the configuration on the device. Moreover, Kubelka munk transformation is used to convert reflectance to absorbance using the following equation:

F(R)=(1-R)^2/2R, where R is reflectance (%R/100). Finally you can plot F(R) vs wavelength data as UV-Vis DRS spectra of your sample.

Agidew Sewnet, thank you, bro! I have DRS data which can be plotted as reflectance vs. wavelength. What I want is without transforming the machine during characterization how we can convert DRS data to Absorbance? And then plot Absorbance vs. wavelength? Some people suggested one equation and it works well but I don't know how this equation is published or not! It is obvious that from the Kubelka Munk function, we can calculate the bandgap of materials (or may know the absorbance edge).

I think from the reflectance plot we can easily find the absorbance edge. That is from the minimum reflectance % value! However, to convert UV-Vis DRS data to Absorbance, some people use the following formula.

A = -1/[LOG10(1/R)]

Dear Fekadu,

The most common way to report UV-Vis DRS spectra in journals is F(R) Vs wavelength instead of Absorbance vs Wavelength. So once you informed how to calculate F(R), do not to hesitate to report it in the above way.