Questions tagged [spectroscopy]
the practice of separating a signal by frequency (or sometimes energy or momentum) and analyzing the resulting spectrum.
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High-purity silicon detector vs HPGe for gamma-spectroscopy
Is it possible to construct High-purity silicon detector for gamma-spectroscopy the same way HPGe detectors are made? Will it work when cooled to the same 77K?
Why HPGe is mainly used for gamma ...
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What is absorbance and Transmittance?
I am currently doing some work in Spectroscopy, and I was wondering how are absorbance, and transmittance related? Do they have a domain, and range, how to read some sample graphs.
I was ...
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What does represents the concept of “magic wavelength” in optical frequency standards?
I cannot find on the internet references on this topic, so I'm trying to post my question on this forum, this is the first time I post here.
I can't understand the difference between "normal" ...
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Are there names for Helium (He) emission lines like the Lyman/Balmer/Paschen series in Hydrogen?
Just wondering if helium emission lines have names like hydrogen lines. For instance the Balmer series is:
$$H_{\alpha}, H_{\beta}, H_{\gamma}, H_{\delta}...$$
The Lyman series is:
$$L_{\alpha}, ...
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Relation between oscillator strengths $\log{gf}$ and the Einstein $A$-coefficient, rotational quantum number, …
I'm analyzing the spectra of M dwarfs. Some authors characterize the lines with the oscillator strengths $\log{gf}$ while others follow different paths with the Einstein $A$-coefficient. I would like ...
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Can a LGL (Lens-Grating-Lens) spectrometer have a non-zero geometry?
I am designing a transmission grating based spectrometer. Can the angle of incidence on the grating (alpha) be unequal to the diffraction angle (beta)?
I didn't think that they could be varied as i ...
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How can we use Electrically detected magnetic resonance spectroscopy to investigate properties of a semiconductor? [closed]
I want to know how what information the Electrically detected magnetic resonance spectroscopy can tell us about a semiconductor like phosphorene (in term of properties, the interaction of different ...
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262 views
What is the cause for the fine structure?
What is the cause for the fine structure? I know that it describes the splitting of the spectral lines of atoms but I don't understand its cause,
any help is appreciated
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Has man ever observed the spectrum of a single hydrogen atom?
Were there this kind of experiment done before?
The spectrum we observed is radiated by huge number of hydrogen atoms in the gas, not by single hydrogen atom.
I know it's very hard to test a single ...
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Rutherford Backscattering spectrometry [duplicate]
I recently read about Rutherford Backscattering spectrometry
and stumbled upon following equation
$$\frac{d\sigma}{d\Omega}=\left(\frac{Z_1Z_2e^2}{8\pi\epsilon_0mv_0^2}\right)^2\csc^4(\frac{\Theta}{2})...
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Are there accepted spectral lines, or wavelength of light emitted, for the various neural and ionized atoms? If yes, where can I find them? [duplicate]
I am working with the redshift phenomena and analyzing the spectral lines of various emissions by galaxies. However, when I came to analyze the change in wavelength I was confused on what to compare ...
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Laser power inside a vapour cell
I have a laser beam whose power I measured to be x $\text{mW/cm}^2$. Furthermore, I measured the beam profile of the laser beam and therefore can estimate its intensity. I shine this laser through a ...
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1answer
32 views
Neutral lithium ionization energy for removing an electron from the $1s$ orbital
How much energy does it take to singly ionize a neutral lithium atom by removing an electron from the $1s$ orbital?
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27 views
Why infrared laser goggle looked orange?
So here's the thing, the laser goggle for UV light looked orange-yellow, which was sort of understandable, cause, if one want to block UV light, then the transmitted light ought to stay away from the ...
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1answer
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What is so special about Paschen, Balmer and Lyman series?
I'm reading McIntyre's QM book and I see the same diagram ever so often:
He goes on to say:
I don't understand what he is trying to say with the last sentence. It seems he is saying, that ...
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1answer
33 views
Formation of Red and blue bands in the sky
Today at the time of sunset I saw this
The sky is divided into two parts one In red and one in blue which are very distinctive
Can anyone tell how?
The upper part of the image points towards the ...
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State coefficient in Kramer-Heisenberg-Dirac formula
I'm following the derivation of the Kramer-Heisenberg-Dirac formula from the book "Modern Optical Spectroscopy" and I'm having trouble understanding the wording and the derivation of the transition ...
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Why luminescence peak can move to higher energies with increasing temperature?
Can somebody explain me, why sometimes I see changes in position of luminescence maximum as temperature dependence in dielectric crystals? Is this is caused by band gap changes or maybe some exciton ...
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What software programs are recommended for background extraction and peak fitting?
I have an energy spectrum for various gamma sources. What software programs are recommended for background extraction and peak fitting in this case?
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Disk-like structures spectra vs ring spectra?
In the introduction to this paper (https://arxiv.org/abs/1803.06423) it is mentioned that disk-like spectra was observed in black hole X-ray binaries, when models would expected to be unstable (...
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Is it possible to do Raman Spectroscopy without having to use a filter?
We are doing our thesis regarding Raman Spectroscopy and we saw that the setup usually includes a notch or edge filter. I understand that it is important in order to remove the Rayleigh scatter of the ...
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1answer
34 views
(What causes) the *other* Compton edge?
The question
If one exposes a scintillator to a gamma source, one will observe two features for each characteristic energy in the source: a photopeak, due to complete absorption of photons, and a ...
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Photo Multiplier Tube (PMT) and charge sensitive pre-amplifier
I have an H7195 assembly type Photo Multiplier Tube (PMT) used to be tested for single photon measurement. I would like to use the dynode output to check the spectrum by connecting to a charge ...
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3answers
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Why hydrogen lines are less visible in the Sun spectrum than in supernovae clouds?
Supernovae clouds are very colorful, and if I trust documentaries I watched, the colors are due to excitation of elements, as in fireworks. Since the Sun is mostly made of hydrogen, I suppose those ...
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What powdered material can be regarded as an ideal Near UV reflector?
I'm looking for some common powder material (like alumina) that's nearly 100% reflective in UV region, to make a compacted power target to use as a reference for 100% reflectance.
Or, at least, some ...
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Is it possible to detect the amount of CO2 in the atmosphere by observing Northern Lights?
From my limited understanding, the different colours observed from the Northern Lights is due to the presence of different gases in the atmosphere. Is it possible to observe the amount of CO2 in the ...
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1answer
59 views
What is 'Spectral Domain'?
In a paper which deals with optical coherence tomography they say they are dealing in the spectral domain. What exactly does that mean?
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49 views
Saha-Boltzmann Equation
I am following Ahmed, Ahmed, Rafiqe & Baig A comparative study of Cu–Ni Alloy using LIBS, LA-TOF, EDX, and XRF paper on Laser Induced Breakdown spectroscopy.
It mentions two versions of Saha-...
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0answers
48 views
Concept of polarization in microwave rotational spectroscopy
I am trying to understand the concept of polarization of molecules after they are excited by a microwave pulse. The context is:
The complexes are produced in a pulsed supersonic jet expansion of a ...
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What does the line strength mean in terms of spectral lines?
In my previous astrophysics lecture we were discussing the spectral types of stars. We were looking at the absorption features of dwarf stars in different spectral classes at a particular luminosity ...
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What does molecular term symbol $X^1\Sigma_u$ mean?
I'm confused about the molecular term symbol, for example:$X^1\Sigma_u$ mean.
The super script $1$ and big $\Sigma$ was kind of like that of atomic term symbol.
However, I'm not sure what does $X$ (...
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2answers
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Plasma inside deuterium spectrum tube?
Hullo,
In a deuterium spectrum tube there is a thin capillary in the middle (see picture) that glows purplish sort of. Now, I wonder what this glowing part actually consist of? Is it a completely ...
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Can the Standing Wave Ratio be deduced from a reflection spectrum?
The Standing Wave Ratio (SWR) is the ratio between the peak amplitude of the standing wave and the trough amplitude of the standing wave.
I would like to figure out the SWR within a thin film when ...
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3answers
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Why are stellar absorption line spectra passed through a cold gas?
I am currently studying spectral lines and saw in my notes that the way in which the absorbtion line spectra for a star was measured was by taking its light and shining it through a cold gas. The ...
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How to calculate the transition energy between $^2P$ to $^2S$ and $^2D$ to $^2S$ for sodium?
It's been known how to calculate the Zeeman effect. However how to calculate the transition energy between $^2P$ to $^2S$ and $^2D$ to $^2S$ for sodium($Z=11$)? ($^2P$ here meant term symbol ignored ...
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Principle series, Sharp series , Quantum defect, in Alkali Spectrum
Could anyone help me to understand the relation ship between principle series, Sharp series(https://en.wikipedia.org/wiki/Sharp_series ), electron spin, and atom's inner magnetic field etc. the ...
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How is “linewidth” defined for a damped driven oscillator?
Suppose we have a damped driven harmonic oscillator governed by the following equation of motion:
$$\ddot \phi(t) + 2 \beta \dot \phi(t) + \omega_0^2 \phi(t) = J(t) \, .$$
In the case that $J(t) = A \...
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Which device to measure UV lamp wavelength with high precision
Which techniques and devices are able to measure the wavelength/frequency of a UV lamp within the wavelength range of 50nm - 300nm?
Is a VUV Optical spectrometer the right device for this?
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Which colour comes out first from a prism?
When a narrow beam of white light is incident on a triangular prism. The speed of red light is maximum and violet is of minimum, red light bends less and travels less distance as compared to violet ...
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1answer
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Selection rules in rotational spectroscopy- water molecule
The University of Liverpool maintains a ChemTube 3D page, where it says
http://www.chemtube3d.com/spectrorotcd0-CE-TEST-ROTATE-ALL.html
*> Highly symmetric polyatomic molecules, such as carbon ...
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Pressure inside spectrum tube?
I asked the firm who sells them here in Sweden, but they didn't know. I asked sellers on eBay, same answer. Is it different with say neon and hydrogen? Or is it the same pressure in all? I'm ...
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1answer
37 views
What's D lines for hydrogen like atom?
Could anyone tell me what's the definition of D lines for hydrogen like atoms?
(Not just those two lines for sodium.)
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1answer
16 views
Pump Probe Spectroscopy using in ultrafast diffraction
I am going through currently the experiments on "Ultrafast Diffraction". Would you please explain with some significant degree of conceptual details how I can find the transverse Doppler shift ...
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60 views
Gamma from U238 decay chain
Where can I find detailed information on the gamma background from the U238 decay chain?
Edit: Thank you for your replies. I need to find all the branching ratios and extract information of all the ...
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1answer
28 views
difference between infrared radiation and infrared night vision
I need th eanswer that are infrared radiation and infrared night vision are same?. Are Infrared night vision camera use IR rays?, if yes then why we use Infrared LEDs around the lens???
I am totaly ...
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1answer
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Experimental Assignment of Electronic Transitions in Atoms (Grotrian Diagram)
Grotrian diagrams often taught in instrumental methods of chemical analysis to chemists. After a decade, I finally found the original book of 1927 by Grotrian "Graphische Darstellung der Spektren von ...
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Is discharge tube dangerous?
Are those gas discharge tubes dangerous?
I found atom spectra interesting, so I booked a 1.5 hour lab session at a local high school. The physics teacher gave me a few hydrogen tubes, helium tubes, ...
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1answer
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What is line broadening phenomenon in quantum many body physics?
I have been reading Anderson's paper, "Absence of diffusion in a certain Random Lattice" and found the concept of inhomogeneous broadening. I couldn't really find a satisfactory explanation with a ...
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1answer
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Why can't the electrons in Lamb-Retherford Experiment transition from 2S to 2P(j=1/2)
This experiment reveals metastable state and uses the fact that an electron in 22S1/2 can't go to the ground state as ∆l=0 is restricted. But I was thinking why doesn't electron go to 22P1/2 and then ...
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Does hydrogen reflect all visible wavelengths other than the wavelengths it absorbs?
I'm confused how reflection and absorption of photons work. For example hydrogen absorbs 4 wavelengths of light, but then that energy is emitted once the electron falls back to its ground state. So ...
