Dear Binod, can you send the data? If you do not want to post them for all, send them privately ... What is the actual energy / wavelength range?
Kind regards, Dirk
Binod - you need to do it yourself, it is very simple. Just need to know that what you call an "absorption spectrum" is a set of values for each wavelength: A = log (initial intensity / transmitted intensity), note it's usually a decimal log used in all the spectrometers. So you now know the ratio of {transmitted intensity} to {initial intensity} and can calculate and plot whatever you want. E.g. by conservation of energy, the {reflected intensity} = {initial} - {transmitted}, etc.
Be careful, people use various different definitions (or meanings) for the word "transmission spectrum" or "reflection spectrum" (e.g. with or without logarithms, for power or the wave amplitude). You need to decide which one you need...
Try using academic version of: http://www.knowitall.com/academic/
register with your institution email ID. You can convert the spectrum yourself.
Dear Binod,
The problem is not well defined. If you have no scattering/reflection, then the sum of the absorbed and transmitted light are = total light intensity. But if you have scattering, even though you see a decrease in light transmitted, it is not possible to say from one spectrum, how much was absorbed, scattered or reflected.
You'd need a separate measurement - perhaps diffuse reflectance, to get the reflected part.
In general, a spectrophotometer working in the solar radiation wavelength region measures either the transmittance or the reflectance of a sample. That is, the absorbance is not measured directly, but is calculated from the measured transmittance and reflectance (if both can be measured). When a spectrophotometer gives you the absorbance A’ on the logarithmic form, i.e. the optical density OD, which is a common output from many spectrophotometers (OD = A’ = log10(1/T), "10" supposed to be as a subscript here, i.e. the 10-log), it is in reality a calculation from the measured transmittance ignoring the reflectance. A spectrophotometer measures the radiation which is collected by the detector from either the transmitted or the reflected beam. Furthermore: T + A + R = 1 (100 %) where T = transmittance, A = absorbance and R = reflectance between 0 to 1 (or between 0 to 100 %). Note that the absorbance A in the above is not the absorbance A’ on the logarithmic form, i.e. not the optical density OD, which is a common output from many spectrophotometers. You may see further details in e.g. chapter 3, 4, 7.6.3 and 7.6.7 in the following article: B. P. Jelle, ”Solar Radiation Glazing Factors for Window Panes, Glass Structures and Electrochromic Windows in Buildings - Measurement and Calculation”, Solar Energy Materials and Solar Cells, 116, 291-323, 2013. In addition, you need to have control over if the transmittance and reflectance are specular (directly transmitted or reflected, i.e. mirror-like) or diffuse (scattered in all directions), where you in the latter case would use integrating sphere accessories to collect the scattered transmitted/reflected radiation.
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