All Questions
Tagged with absorption photon-emission
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Absorption and emission spectrum terminology
Hi everyone recently i was looking for laser crystals and since I am an autodidact i was confused by the terminology and units of the optics domain. And specialy by the absorption and emission ...
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How can the inverse of stimulated emission be distinguished from "normal" absorption?
A simple system with two energy states can absorb an incoming photon (of adequate energy) to get excited, and it can relax by either spontaneously emit a photon afterwards or get stimulated by another ...
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How do we know that the Sun is 71% Hydrogen by mass from emission/absorption spectra?
In my Intro to Astronomy ("intro" is very important, please keep responses as simple as possible) course, we're currently learning about light and electron orbitals and such, and I came ...
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Formation of emission lines, absorption spectra
If we spectroscopically observe a cloud of hot gas, which is on the whole not very absorbent, and which is not illuminated by a source behind it, we observe emission lines. How does this type of ...
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Density of final states in photon absorption/emission by a hydrogen atom
Consider a hydrogen atom in an electromagnetic field. The Hamiltonian is of the form
$$\hat{H}=\underbrace{\frac{\hat{p}^2}{2m}+V(r)}_{\text{atom}}+\underbrace{\sum_{\vec{k},\sigma}\hbar cka^{\dagger}...
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Material that is one-sided translucent [closed]
Is there a polymer material that is translucent from one side but not from the other side?
I want to build some custom push buttons that should appear completely black. Only when they are led by an ...
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Why do different metals glow with different colours if all solids have the same emission spectrum?
Why do different metals glow with different colors if all solids have the same emission spectrum? According to my teacher, all solids have the same emission spectrum at the same temperature due to ...
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If all matter can emit at all wavelengths, can all matter absorb at all wavelengths too?
Based on Planck’s law all matter can emit at all wavelengths at different intensities dependent of temperature. I was wondering if this holds true, does all matter absorb all wavelengths too, at ...
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What accounts for a Lyman-break for all wavelengths shorter than 91.2nm if the Lyman limit is the highest energy photon that Neutral hydrogen absorbs?
From this description of Lyman-break galaxies, I don't understand how:
...radiation at higher energies than the Lyman limit at 912 Å is almost completely absorbed by neutral gas around star-forming ...
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Why can Einstein coefficients be derived based on thermodynamically equilibrium relations when they are basically intrinsic?
Einstein coefficients for emission and absorption ($A_{21}$, $B_{12}$, $B_{21}$) are often derived from a consideration of thermodynamic equilibrium using Boltzmann statistics and comparison with ...
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Trouble with Einstein coefficients - what is the meaning of the transition probability?
Perhaps it seems to be a not very intelligent question, but I am unfortunately not able to understand what the probability per second that a molecule will absorb a photon is, as part of the theory of ...
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Why does light behave differently when interacting with multiple particles?
When light hits an atom (I will use a carbon atom for simplicity), if it is not in the absorption and/or emission spectrum of carbon, it will simply pass through without interacting with the atom. ...
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Why does light not pass through opaque objects? [duplicate]
Since light is massless it does not interact with particles unless that specific wavelength is on the emission and absorption spectrum.
The emission and absorption spectrum of an atom indicates the ...
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What is the relationship between emissivity $\varepsilon$ and the imaginary part of relative permittivity constant $\epsilon^{''}_{\rm r}$ if any?
In terms of the Stefan-Boltzmann law a body that does not absorb all incident radiation emits less total energy than a black body and is characterized by an emissivity $0<\varepsilon <1$ such ...
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Is photon emission the time-reversed process of photon absorption?
Say we have an atom on which we shoot a photon. Is the process of absorption the time reversed process of emission? I can't imagine the two processes being the same, although in both cases the photon ...
