the practice of separating a signal by frequency (or sometimes energy or momentum) and analyzing the resulting spectrum.

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Bandwidth-Pulse Duration Relationship

Assuming Gaussian pulse, the relationship between pulse duration and bandwidth is given by: $$\Delta \nu \cdot \tau \geq 0.441$$ If the rms bandwidth and rms pulse duration are used, then the ...
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16 views

Why is fluorescence often associated with Raman scattering?

In Raman scattering, the Stokes signal is at a longer wavelength compared to the excitation signal, leading to fluorescence. Why is it the case that this would lead to fluorescence? I don't ...
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Which g factor in an EPR spectra is the right one?

I was reading this introduction to EPR and it seems to imply both that there is a unique g-factor of a given compound, but also that we can calculate multiple g-factors for a compound. For example, ...
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71 views

Is it possible to reconstruct the wavefunction of a molecule from a collection of spectra?

Spectra of a molecule can be calculated if the wavefunction is known. Is it possible to do the opposite?
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26 views

What's the difference between microscopy and spectroscopy?

Both methods collect particles or electromagnetic waves, and in both methods it's possible to reconstruct a 2D image, which may represent morphology (AFM, LEED for example), electronic structure (STM, ...
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39 views

Where can I find spectral data for materials?

The chemical library of ChemSpider has a dedicated section for spectra, but I haven't found any materials that have such data. Is there a (public) database of spectral data?
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45 views

Is there a correct yet more compact way to write these equations?

I've got the following equation which denotes the total absorbance $A$ as determined by the sum of the absorbances of individual molecules: \begin{equation} A(\nu,c_{1},...,c_{n}) = \sum_{mol=1}^{n} ...
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What's the difference between “spectromicroscopy” and “microspectroscopy”?

Both definitions that I found are rather vague. (Related question: What's the difference between microscopy and spectroscopy?)
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Moisture measurement through PVC using spectroscopy

Is it possible to measure moisture content in a blister through a PVC layer? The distance that the laser will have to travel will be around 3-3.5 mm. The thickness of PVC layer is 100 micron. I was ...
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Fermi's understanding of the Doppler effect

I am now reading the classic paper by Dicke, The Effect of Collisions upon the Doppler Width of Spectral Lines At the very beginning of the paper, Dicke said ''Quantum mechanically, the Doppler ...
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23 views

Switching a PMT from PC-mode to DC-mode: What happens?

I was wondering a bit how it is possible to switch a photo multiplier tube from the photon counting mode to the DC (I assume direct current)-mode. If I simply add a high voltage (as usual), I get the ...
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How to distinguish Shake-Up Satellites from Plasmons?

I am studying XPS spectra (X-ray Photoelectron Spectroscopy) at the moment. In XPS, different processes can influence the final state energy of detected electrons. One of these processes is the ...
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Help Interpreting Ultraviolet Photoelectron Spectroscopy (UPS) data

I was given a batch of UPS data without any background other than the materials examined and I don't have any experiencing interpreting it. I wanted to reach out to some experts (hopefully, someone ...
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48 views

Photon yield of NaI

We have to calculate the photon yield of the scintillator NaI. We have measured his pulse height spectrum but we have no idea how to solve this problem. Can someone explain it? The source that we used ...
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37 views

pGRE question on natural line width

The lifetime for the $2p \rightarrow 1s$ transition in hydrogen is $1.6 \times 10^{-9}$ s. The natural line width for the radiation emitted during the transition is approximately... Their solution: ...
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Is there any application for an advanced spectrometer in geometrical optics experiments?

We have an advanced spectrometer in our geometrical optics lab! I'm seeking for any experiment in geometrical optics to include it!
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297 views

How are problems in astronomical spectroscopy solved?

Astronomers based on the ground telescopes, watch the stars and make predictions about them based on the spectrum of light. But when the light from those stars reach the telescopes through the ...
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Explain materials with 4 fold symmetry having same reflectance when shone with LCP and RCP

This is my first post here. I am currently reading "Optical planar chiral metamaterial designs for strong circular dichroism and polarization rotation" by Do-Hoon Kwon, Pingjuan L. Werner, and ...
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34 views

How are different wavelength components collected by the same detector in a spectrometer?

Let's think, we have a detector array (128x1 and each CMOS detector responds 400 to 1000 nm TSL1401CL that way, each detector has 4.6875 nm interval). Then, basically in a spectrometer a prism reflect ...
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Hydrogen spectrum intensity using a monochromator

Using a monochromator (350->800 nm) and a hydrogen gas lamp, I find this spectrum : We can see 3->2, 4->2, 5->2 transitions from Balmer series, but not 6->2 (which we should expect at 410 nm). As ...
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83 views

What does a hot, optically thin gas *look* like?

In another question I tried to answer what a sample of the Sun's photosphere or core would look like, if it could be brought into the lab. Here is a broader question - if I have a small inert ...
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39 views

Spectrometer vs. Spectrophotometer

I have been researching about the difference of a spectrometer and a spectrophotometer. They both sound the same. What is the difference?
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31 views

What is harmonic and fundamental bands in IR spectroscopy?

What is harmonic and fundamental bands in IR spectroscopy? I'm trying to find exact definitions. I guess that fundamental is $1\leftarrow 0$ transition (the most intense and energetic) and harmonic ...
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39 views

Why doesn't the color of an object change when signal of different frequency impinge upon it?

Correct me if I'm wrong but I've always thought that the color that an object has is due to the oscillation of the atoms that makes up the material of that object. When white light is shine upon an ...
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Reason behind formation of doublets in diffraction spectrum

like if you see is Sodium (and also in Mercury), there are two discrete lines of Yellow color.. What's the reason behind formation of doublets?
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Why is the color of fire is yellow or blue sometimes? [duplicate]

If you light up any thing it burns in yellow and as well when you light up a gas stove it burns in blue color. What brings this color change?
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What methods are there to obtain flourescence?

Blackbody radiation is fairly easy to obtain. However, Atomic Emission spectrum based on fluorescence requires more work and provides more information. Traditional methods use a flame or plasma to ...
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Spectroscopy Question

So if we were to view the visible spectrum of a white dwarf star. Would the planetary nebula essentially block what would be an absorption spectrum? If so, would we all just see emission lines. I'm ...
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What's the difference between frequency domain and time domain spectra?

If I have a mechanical oscillator and want to observe the dynamical behavior of the oscillator, is there any additional information to observe it in time domain and frequency domain? Normally, we ...
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What is “Lifetime Intensity” in photoluminescence?

I'm reading an article "Surface plasmon enhanced Förster resonance energy transfer between the CdTe quantum dots". Link The reasearchers are writing about increase in "lifetime intensity" and even ...
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Vibrational quantum notation

Reading articles on spectroscopy I often see this notation: 30001 <- 01101, 00011 <- 00001 in context of molecular ...
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Spectroscopic notation for more than one excited electron

In spectroscopy, notation like $^3S_1$ or similar is often used to define atomic states. This is unambiguous when considering only a single electron excited from the outermost energy level. But how ...
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83 views

Total magnetic moment in an atom

I have a doubt regarding the calculation of total angular momentum of electron in an atom. Which is the right way to do it? Method 1: Total magnetic moment $$ \begin{align} \vec{\mu_J} &= ...
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64 views

What is the 'triangle selection rule' in spectroscopy?

This paper states that However, the multiphonon relaxation bridging the $^5\!D_1$ and $^5\!D_0$ levels is a well-known exception because it is formally forbidden by the triangle rule and occurs ...
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30 views

How does change of pressure affect molecular rovibrational bands position and width?

Lets say I have $CO_2$ gas chamber with pressure $P_0$. How do rotation-vibrational transition bands alter when I change pressure P? Do they shift or not and why?
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Homemade Spectrometer

Recently I have had ideas of how to build a spectroscope, but I'm not sure if it will work. As can be seen in the diagram, the experiment is simple: it consists of a laser that generates the light ...
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Doppler effect for the electrons emitted from ions moving at a particular velocity

If I have ions moving in X axis (along both directions; positive X axis and negative X axis) and if I irradiate laser along the positive X axis, electron will be ejected from the ions (if I am using a ...
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Machine to identify substances

I was looking at Wikipedia's article on mass spectrometers, and realized that the method described was to heat a sample into its gas phase and separate the ions by mass using a large magnet. While I ...
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Is the emission spectrum of a muonic atom different?

From my quick investigation, the spectrum is based on the Rydberg formula, and with a small change, would lead to $$ {1 \over \lambda_\mu} = {m_\mu \over m_e} \left( R \left( {1\over n_1^2} - ...
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Why is cesium used to measure time in atomic clocks?

Seconds are measured by the frequency emission of cesium. Why is a frequency from the emission spectrum of cesium used as the standard in defining a second? Why particularly cesium?
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155 views

Can this simple spectrometer be precise without collimation?

Consider the following spectrometer structure: Here the slit can be changed in size, and the lens and detector can be moved closer to or farther from the diffraction grating. I was trying to get ...
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32 views

Hydrogen Spectra [closed]

I am talking about hydrogen spectral lines such as Lyman, Balmer etc. In order to make those spectral lines series more than one electron are needed to jump from higher orbits to lower orbit. But ...
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23 views

Appearance of the recomposition of a given spectrum? [duplicate]

Given a visible spectrum, i.e. a function from the set of visible wavelengths into the set of intensities, I would like to see the color having this spectrum decomposition. Question: How can I do ...
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Dielectric resonance spectroscopy of thin and thick film

How does the technique vary for dielectric resonance spectroscopy for thin film of ~ 3 micrometer and a relatively thick film of 100 micrometer?
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129 views

Do all elements spectrum lines fall within the visible light range?

I was wondering if whether we were extremely lucky to have found spectral (absorption) lines of astronomical objects because they fell within the visible light range or if there something intrinsic ...
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20 views

What is the difference between Linear and Non-Linear Magneto-optical effects?

Principle difference between Linear and Non-Linear Magneto-optical effects and how they affect the property of light passing through a Vapor medium.
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99 views

Autocorrelation function for deterministic nonlinear dynamical systems

I am quite puzzled with the problem that spectral analysis has been either applied to noisy dynamical systems or to chaotic ones. I was wondering why nobody makes analysis of non-linear dynamical ...
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62 views

Continuous spectra of photons

I guess this is a basic quantum mechanics problem, but I'm not entirely sure of my answer. Suppose we have an electron in a hydrogen atom having the state \begin{equation} ...
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1answer
55 views

What happens to light at sharp points? [closed]

At the tip of the sharp point shown, what will happen to light incident on it. This curiosity was invoked by a friend and also my childhood of watching shiny pointed swords in cartoons. Original ...
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What are the current size limitations of NIR spectroscopes? [closed]

So few days ago I came across this new tool for smart phones http://www.consumerphysics.com/myscio/. It says it uses NIR spectroscopy, which I don't know lot about. My question is: Is it possible for ...