# Questions tagged [absorption]

A transition by which the energy of at least one photon is completely transferred to a material.

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### Why the extraterrestrial solar spectrum is higher than blackbody spectrum? [duplicate]

I am reading "Radiation Heat Transfer by Michael F. Modest(2003)" and the author talks about how the solar spectrum can be approximated by black body radiation at 5777K. I'm finding the plot ...
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### Energy of exciton formation in semiconductors

Many sources I've seen have alluded to: An exciton can form when a material absorbs a photon of higher energy than its bandgap I looked at absorption enhancing effects of excitons, and am aware of ...
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### What variables affect an object's absorption of invisible light?

Say I have two objects (we'll call them object $1$ and object $2$) of the same material but of a different colour, placed at the same distance away from another object (we'll call object $3$) that ...
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### Balmer series for ionized lithium

I am trying to calculate the wavelength for the first spectral line in a Balmer-series for a two times ionized lithium, $\text{Li}^{2+}$. I know that the atomic number $z$ is 3 for lithium and it is ...
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### Excitons - Increase in absorption

I have consulted a book by Mark Fox on Optical Properties of Solids, and it states: " The absorption of a photon by an inter-band transition in a semiconductor or insulator creates an electron in ...
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### Absorption and emission spectra

I had this exercise on a test the other day and I still don't know how to solve it. Being given the image below, I have to say what's the type for each spectra, absorption or emission. I didn't find ...
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### Nonlinear Absorption Coefficient

How is Absorption Coefficient related to Susceptibility. I want to find linear, 3rd and 5th order absorption coefficient from linear, 3rd and 5th order susceptibility.
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### Is it possible to achieve Invisibilty? [closed]

I read that mirrors absorb only a small amount of light(1-2%). And recently MIT engineers developed the "Blackest Black"(blacker than Vantablack) which reflects only 0.005% of the light. Let's say we ...
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### How is absorption integrated in the simple Drude model?

What is the physical process of absorption in the Drude model? As far as I understood in the Drude model you only consider the electrons as classical particles and frozen ions. No other particles ...
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### How does the attenuation coefficient of white light in water compare to the attenuation coefficient of monochromatic light in water?

So, from what I understand, different wavelengths of visible light, when shone through water, will have different attenuation coefficients due to scattering and absorption from the water molecules. ...
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### What happens to oxygen during atmospheric absorption of radiation with a peak at 60 GHz

This question discusses atmospheric absorption of radiation (specifically 5G radio waves) due to oxygen at 60 GHz. I would like to know exactly what happens to oxygen in all its forms (be it air or ...
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### Are there anti-reflective paint other than black matt paint?

I am trying to build a box where I will be testing some materials inside the box to take measurements of the irradiation. I need to make it so that the walls of the box do not reflect any radiation (...
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### Why do satellite methane detectors use some spectral lines and not others?

I was reviewing absorption/transmittance spectra and was wondering why certain wavelengths are chosen for detectors and not others. Take methane for example For small electronic IR detectors they ...
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### How to picture vibrational overtones of water?

Im trying to understand the colour of water. The absorption occurs because of some of the vibrational overtones of water. The absorption band at 698 nm (14300 cmā1) is a 3rd overtone (n=4) The ...
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### Absorption cross section for Nitrogen in the visible spectrum

I am trying to find data for the absorption cross section of Nitrogen at various wavelengths in the visible spectrum (~400-800 nm). I can only find data at lower wavelengths, however. Data from the ...
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### Momentum matrix elements for two-photon absorption in semiconductors

I am trying to follow the paper "Two-photon absorption with exciton effect for degenerate valence bands" (to be found here: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.9.3502). It gives the ...