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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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1answer
41 views

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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24 views

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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34 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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31 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
65 views

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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36 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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21 views

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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11 views

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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2answers
62 views

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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27 views

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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21 views

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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71 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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60 views

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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69 views

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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14 views

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
199 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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64 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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50 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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35 views

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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2answers
59 views

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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26 views

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
646 views

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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45 views

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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82 views

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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56 views

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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28 views

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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263 views

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
70 views

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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32 views

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
41 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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69 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
33 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
75 views

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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1answer
99 views

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
58 views

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
70 views

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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1answer
43 views

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 ...
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7 views

second-harmonic generation and inversion centers confined to a planar defect

Let's say that we have a phase which breaks inversion symmetry. Now lets say two domains of this phase meet at a plane such that the whole system now has inversion symmetry, with the inversion ...
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34 views

How can I determine, in what extent the fit to experimental data is good in Matlab?

I have experimental spectrum in which y-axis is intensity values, and x-axis is frequency values. Int - array of experimental intensities (y-axis). w - array of frequencies (x-axis). I know the view ...
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1answer
45 views

Light source needed in colorimeter and a spectrometer

I've found myself doing some research to ascert the differences when trying to assess the colour of a given sample. I've found two main options, which are (1) a colorimeter and (2) a spectrometer. ...
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1answer
59 views

Predicting spectral lines

In the spectrum of some hydrogen-like ions the three lines are known, which belong to the same series and have the wavelengths 992, 1085, 1215 angstroms. What other lines can be predicted? I don't ...
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44 views

Fourier Coefficients

Suppose i've a two voice samples v1 and v2. Comparatively voice v1 is louder than the v2. If both the voice is spoken by the same person.(Spoken normally as he speaks) Is it good to state the ...
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2answers
567 views

What is the purpose of the slit in a spectroscope?

I built a spectroscope using a CD as diffraction grating. I understood how the grating works, but I didn't get why the slit is essential. Shouldn't it work even without the slit?
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1answer
49 views

How did Edwin Hubble estimate the velocity of distant stars?

I didn't know how to be succinct with my actual question in the title. My question is, how did he separate the components of the actual velocity of stars from that of the velocity due to recession (...
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67 views

Degenerate and Non-Degenerate Pump Probe Spectroscopy

I have just started my Msc Project, working on Pump Probe Spectroscopy. I will be most probably trying to setup a non degenerate pump probe technique, with the setup for degenerate type already done ...
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1answer
58 views

How was the electron in Rutherford's model producing a continuous spectrum and not a line spectrum?

How was the electron in Rutherford's model producing a continuous spectrum and not a line spectrum? What is the logical thinking behind that it will produce a continuous spectrum?
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100 views

What are good, reliable databases of atomic spectra?

I am looking for a database of atomic spectra, which contains atomic levels and their energies, electronic configurations, angular-momentum characteristics and lifetimes, and atomic transitions and ...
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1answer
25 views

Principle of Energy Dispersive x-ray Spectroscopy

I have a question about the EDS I don't understand how the detector can differentiate the Energy of incident x-ray simultaneously. In my thought, the emitted x-ray from the sample have different ...