Questions tagged [absorption]
In chemistry, absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – gas, liquid or solid material.
86
questions
2
votes
0
answers
32
views
Sensitivity of CoSi2 to hydrogen
It is known that palladium is quite sensitive to hydrogen, i.e., has an extraordinary ability to absorb hydrogen. I was reading a paper that talks about the fabrication of a Pd based sensor for ...
2
votes
1
answer
193
views
Ozone from 10um IR?
Ozone is easily produced by Hg lamps with <200nm power (peak@185nm), but O2 also strongly absorbs around 10um. I've poked around but can't find any discussion of ozone production at 10um. Is the ...
2
votes
0
answers
61
views
Difference in the absorption spectrum of gaseous atoms and complex ions
An absorbance spectrum is a graph that shows how much light is absorbed by the material at each wavelength of light. Both spectra are due to electronic transition, but for gaseous atoms, this spectrum ...
3
votes
1
answer
507
views
How to find the infrared absorption spectrum of O2 and N2?
I am new to spectroscopy, so I am not sure how my questions are perceived. I just want to make sure that I am not lost, so any kind of suggestion is welcome.
I am interested in the infrared absorption ...
2
votes
0
answers
64
views
Negative absorption coefficient
What does a negative absorption coefficient mean?
In detail - I participated in a Synchrotron virtual laboratory. I have to analyze the results and understand what a negative absorption coefficient ...
1
vote
1
answer
85
views
UV-Vis Absorption Spectra climbing at lower wavelengths
I have run a sample of Pyrene in Ethanol and got a UV Vis absorbance spectra that starts climbing as it reaches the lower wavelengths. I am using quartz cuvettes and was wondering what could be the ...
1
vote
0
answers
154
views
Color of coordination compounds
My book(Page $259$ section $9.5.5$) says that the color mainly comes from absorption of light in the coordination compound:
The color is complementary of the wavelength it absorbs , the wavelength ...
3
votes
0
answers
39
views
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 ...
2
votes
0
answers
62
views
Auxochrome groups and red shift
Wikipedia states that "An auxochrome is known as a compound that produces a batochromic shift, also known as a red shift because it increases the absorption wavelength, thus approaching infrared ...
-3
votes
1
answer
56
views
Does ionization energy play a role in absorption spectrometry of non metals? [closed]
Absorption spectrometry is useful for analysing metals in the samples. But it's not recomended for non metals though. I know that it's difficult to analyse non metals because most of them absorbs in ...
1
vote
0
answers
102
views
Calculating Band Gap Energy When Absorption Spectra Shifts with Concentration?
I am not a chemist. However, from some experimental work I have been doing, I have found that the intensity of the spectrum changes with dilution, this makes sense. However, when calculating the band ...
7
votes
4
answers
627
views
When pigments absorb light only around a single particular wavelength, why aren't they still white?
I'm trying to understand how organic molecules get their colour.
One major factor are conjugated double bonds which create delocalized pi-orbitals (e.g. https://en.wikipedia.org/wiki/...
0
votes
1
answer
1k
views
Normalized absorbance/transmittance definition [closed]
In the absorption spectroscopy we can calculate transmittance $T$ of a given sample by comparing how the intensity of the incident beam $I_{0}$ is decreased with the distance (Lambert-Beer Law).
$A = -...
5
votes
1
answer
494
views
The reason for selection of wavelengths in the spectrophotometry of Quinoline Yellow SS
The absorption spectrum for Quinoline Yellow SS has peaks at 224 nm and 414 nm, and a trough at 337 nm.
This experiment (see page 31), selects 224, 337 and 414 nm to be used in the spectrophotometric ...
-1
votes
1
answer
955
views
Solubility of nitrogen dioxide in sodium hydroxide
I know $\ce{NaOH}$ can absorb $\ce{NO2}$, but I could not find any data of solubility of $\ce{NO2}$ in $\ce{NaOH}$ at room temperature and atmospheric pressure.
I am trying to figure out how much NaOH ...