What is the best program for calculating the mass absorption coefficient of the elements?
Hello,
It may be too late to answer but experimentally, the absorption coefficient (α) can be calculated from this simple relation:
α = 1/t ln [(1-R)2 / T]
where t is the sample thickness, T and R are the transmission and reflection.But if you don't have T and R and you have Absorbance, then:
absorption coefficient (α) = 2.303 A / t
where (A) is absorbance and (t) is thickness of thin film.
Moreover, You can get the value of Eg by usually use the Tauc relation, which is given by this equation:
αhν = A (hν - Eg )n
while (hν) is the photon energy, where:
hν(eV) = 1240 / [incident wavelength (nm)]
Now, If you plot a graph between (αhν)1/n versus (hν), then you can get a straight line. This line intersects the X-axis at (αhν)1/n = 0 . The values of Eg have been estimated from this intercept. The value of n is dependent on the electronic transition type. Where:
n=1/2 for direct allowed transition,
n= 2 for indirect allowed transition,
n=3 for direct forbidden transition and
n=3/2 indirect forbidden transition. You should try to select the suitable n according to your samples and their preparations.
And reading these links can be helpful
https://doi.org/10.1155/2014/901465
https://physics.nist.gov/PhysRefData/XrayMassCoef/chap2.html
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