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Questions tagged [emission]

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How can H2 emit light with only 2 molecular orbitals?

I know that light is emitted when an electron is excited to a higher energy state and then decays back to its ground state, emitting a photon whose energy corresponds to the difference in energy of ...
Manny's user avatar
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3 votes
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Detection of contamination from salicylic acid via either single excitation fluorometer or via absorbance

My colleague detected fluorescent contamination likely from salicylic acid in some water samples. I have made a new batch and want to check whether my new samples also have this contamination. 1. Can ...
claire's user avatar
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Is vibronically resolved spontaneous emission temperature dependent, following a distribution defined by the canonical density operator?

Does the lifetime of a molecular excited electronic state, for example the $S_1$ state, suffice for thermal equilibration before spontaneous emission occurs? For example the fluorescence of coumarine, ...
Hans Wurst's user avatar
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2 votes
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Emission Spectra Light Wavelength Deviations for Mercury

The Problem: Inconsistencies between the measured and true values of mercury's spectra light wavelengths emitted following a laboratory experiment. What I Know: The experiment conducted was viewing ...
Matt's user avatar
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Measurement of actual carbon dioxide mass emitted from a diesel engine

I was wondering if there is a method to measure the actual total mass of carbon dioxide $(\ce{CO2})$ emitted from a diesel engine used for power generation. Infrared $\ce{CO2}$ sensors generally ...
AEW's user avatar
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Fluorophores with high quantum yield and low lifetime

Does anyone know of any fluorophore or family of fluorophores with a relatively high fluorescence quantum yield (larger than 0.1) and a short lifetime (below hundreds of picoseconds)? I have been ...
Paul Logan's user avatar
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1 answer
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Where do electrons jump to when they jump to next shell in emission spectrum? Why are there no emission lines for jumps btwn orbitals, same shell?

In the emission spectrum, do electrons that jump up to the next shell go to any orbital in that shell? Or if the electron is originally in say the p orbital, does it jump to the next p orbital in the ...
Savannah Castrillo's user avatar
3 votes
3 answers
622 views

How to Combine an Emission spectrum into a colour? [closed]

I am trying to wrap my head around the flame test, and for the most part, it is making sense. My question is their a way to figure out the colour of a flame of an unknown element given the emission ...
Yak's user avatar
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How can I set up and process my excitation-emission matrices properly?

I'm running EEMS on some water samples on a Horiba Fluoromax 4 spectrofluorometer. Method below. $\pu{240-580nm}$ emission, $\pu{5nm}$ interval, $\pu{1nm}$ width. $\pu{240-480nm}$ excitation, $\pu{...
dogman's user avatar
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7 votes
1 answer
805 views

Does all fire only emit light on its outermost shell?

This question is about light emission, which may overlap with physics, but I am most interested in combustion and types of flame (incandescence, petrochemical fuel flames, nuclear reactions). Consider ...
dubious's user avatar
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What type of spectroscopy can display several vibrational energy levels around the electronic transition?

My question is illustrated as the figure. As far as I know, due to the Franck-Condon principle, the absorption spectrum is related to the ground state to the excited state with the same geometry. Here ...
kote2021's user avatar
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How to think about absorption and emission rates and intensity for stimulated emission?

I learned Fermi's Golden Rule applied to absorption and stimulated emission and encountered the following question: Since absorption and emission rates are the same for stimulated emission, why can't ...
ferris's user avatar
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3 votes
1 answer
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Photodissociated iodine laser and population inversion

Iodine molecules ($\ce{I2}$) can absorb in the visible region and dissociate into $\ce{2 I^.}$ radicals. One of the I atoms is in ground electronic state $\mathrm{^2P_{3/2}}$ and the other I atom is ...
S R Maiti's user avatar
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4 votes
1 answer
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Absorption and emission at same wavelength?

Is it possible for a molecule to absorb and emit at the same wavelength? What is the reason behind it? I’m working on charged tin porphyrins and got the excitation and emission (fluorescence) ...
Pavithra J's user avatar
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1 answer
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Detectable elements using flame AES

I've been looking for extra information concerning flame atomic emission spectroscopy. I need a clear overview of which elements are detectable with this technique, but I can't find anything because ...
WilGos's user avatar
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Thermionic Emission Conservation of Energy

I am learning about thermionic emission and how it led to the vacuum tube. It is said that thermionic emission was a way to increase the flow of electrons from a signal (e.g. in a radio receiving a ...
Malcolm McClintock's user avatar
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Temperature dependence of emission lines from gases, for example, neon

Emission lines from Ne are frequently used as wavelength standards in spectroscopy. Reading around Wikipedia, I found about the Paschen law regarding the voltage required to start a discharge. My ...
ankit7540's user avatar
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