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

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174 views

Is there a difference between “two photon absorption” and “double quantum transitions”?

Wikipedia has articles on two photon absorption. And a lot of NMR literature refers to double quantum transitions. But is there a difference? As far as I can tell, a double quantum transition is has ...
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135 views

Interchange symmetry for states with identical particles

I was reading this web page about interchange symmetry for states with identical particles here: http://quantummechanics.ucsd.edu/ph130a/130_notes/node317.html The article states that the highest ...
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28 views

Book on spectroscopy (line dependency on parameters)

I am trying to find a book (undergraduate level) on Spectroscopy. I am interested in how molecular absorption lines depend on parameters like temperature and pressure (for example with gases). Can ...
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37 views

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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55 views

Quantum description of Raman effect

In the classical description of Raman effect the object of study is the electric polarizability of the system. Since I'm interested in learning the quantum description of the Raman effect and in ...
3
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60 views

SHS Interferometer and diffraction limit

I'm currently researching Spatial Heterodyned Spectrometers (SHS) and I'm a bit at a loss understanding the influence of the diffraction limit. I'll be measuring a diffuse visible light source with ...
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54 views

Estimating temperature with Boltzmann relation with split emission lines

I'm trying to estimate the temperature of a plasma through the use of hydrogen lines, $H_{\alpha}$ and $H_{\beta}$ using the Boltzmann relation: $$ \frac{ n_{2} }{ n_{1} } = \frac{ g_{2} }{ g_{1} ...
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22 views

What is the origin of the naming convention for the various branches in vibration-rotational spectroscopy?

In vibration-rotational spectroscopy, the different spectral lines are grouped into branches for different changes in the total angular momentum, i.e. $$ \begin{array}{rrrrrr} & \mathrm{O} & ...
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49 views

In what cases would using a non-resonant spectroscopy be preferable to using the resonant type?

Here it is mentioned that non-resonant Raman spectroscopy is desirable for avoiding fluorescence and for studying water due to water's low polarizability. How is non-resonant Raman desirable in the ...
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56 views

Spectroscopy from a classical light wave or photon only?

In chemistry we mostly regard light/electromagnetic radiation as a beam of particles or photons. This is a very useful model to explain molecular excitations and ionisations from quantum interactions. ...
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34 views

Sonoluminescence spectrum

During cavitation created by sound in a liquid the collapse of the bubbles can lead to very high temperatures and pressures resulting in the emission of light - sonoluminescence. Can the spectrum of ...
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118 views

How to deal with coma and oblique spherical aberration in a Czerny Turner configuration?

I am modelling my own spectrometer using Zemax when all of a sudden I've been told that: even if you manage to optimize the angles or positions of the grating and the mirrors, you won't get ...
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49 views

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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56 views

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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32 views

Vibrational quantum notation

Reading articles on spectroscopy I often see this notation: 30001 <- 01101, 00011 <- 00001 in context of molecular ...
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116 views

Line-shape asymmetry in undergraduate Hydrogen-Deuterium experiment

I'm working as an LA (undergraduate TA) for an undergraduate physics laboratory experiment where students test the Bohr model and use reduced mass to determine the approximate mass of the neutron. In ...
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53 views

How large would the electric field need to be to split the mj -/+1 626.6 nm line of neon?

I am an undergraduate considering an extension on a quantum beats experiment with neon. The premise is to excite neon atoms coherently from a metastable 'ground' state into a superposition of excited ...
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15 views

How to calculate the magnetic field due to orbital angular momentum in the fine structure

How to calculate effective magnetic field due to the angular momentum L in an atom like Na(23)? I found an answer that we could imagine the case that the atom was orbiting the electron now and ...
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25 views

Variable speed of light impact on spectral absorption lines in distance luminous objects?

There are many other arguments as to the constancy of the speed of light (or more precisely, c). One thing I have been curious is what would the impact be on spectral measurements from distant ...
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43 views

Quantum beats and Quantum mechanical side of photosynthesis

I have two questions. One concerning quantum beats alone, another - process of photosynthesis. I am very well aware that there is strong evidence suggesting that mechanism that leads light through, ...
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27 views

Can one measure experimentally the average distance between the two electrons in the excited state of helium in the singlet versus triplet states?

$\frac{1}{\lvert\ \vec(r_{1})-\vec(r_{2})\rvert}$ is a hermitian operator so I am supposing there could potentially be an observable with this which might be experimentally measured. We can measure ...
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12 views

Diffusion of magnetization (NMR)

In the context of MRI I'm trying to understand the mechanisms of magnetization diffusion. Consider a sample that is magnetized by an external magnetic field. We have displacement of magnetic moment ...
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18 views

Modelling populations of GE isotopes

I asked a question similar to this here: What combination of stable GE isotopes make up the germanium in a Ge(Li) spectrometer And got some very good answers. This question is instead based on the ...
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37 views

Coincidence summing in gamma spectrum

Question on coincidence summing here. I've been reading about the coincidence summing effect when a radionuclide has two energy levels that decay to another state in rapid succession. There is also ...
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65 views

Activation energy of luminescence

Assuming that activation energy is constant for some range of temperature, it can be determined from the slope of the plot: $$\ln{I}=A-\frac {E_a}{k_bT}$$ where $I$ - intensity , $E_a$ - activation ...
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44 views

Using stellar spectroscopy to measure stellar parameters, why is it log g?

Stellar spectroscopy can in principle measure the stellar surface gravity, radii, effective temperature, and stellar rotation. Why is it that surface gravity g is ...
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100 views

UV absorption decrease with an increase in concentration

I am working on a project measuring the absorbance of a solution which contains surfactant and hard brine. The solution has a constant concentration of surfactant and varying concentration of hard ...
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33 views

PM-IRRAS Equidistant Fringes in Spectrum

What is the cause, and best method to prevent / minimize, fringes in one's FTIR (PM-IRRAS) spectrum on samples deposited on a thin metal film? The fringes look as though they are spaced out by a ...
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62 views

Can anybody explain about phase shift and phase spectrum terms in case of multidimensional signal?

I know about phase of a 1D signal, but when I move into higher dimensions like 2D or 3D etc, it becomes headache to grasp the concept. What do the terms "phase shift" and "phase spectrum" mean in ...
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49 views

Why graphene's substrate is important

I just have some feelings that somehow it is important what specific subtrate is used to grow graphene monolayer on. Some substrates are better, another ones are not so good. But I cannot completely ...
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89 views

Angle-resolved photoemission spectral (ARPES) function from band Hamiltonian

I am trying to derive spectral function for a band Hamiltonian. I am using http://arxiv.org/abs/cond-mat/0306084 as a prototype reference. I do not understand how the coherence factors $u_k$ and $v_k$ ...
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65 views

Rotational Spectrum of a Diatomic Molecule

The rotational energy levels of a diatomic molecule are given by $$E_l=\frac{\hbar^2}{2I}l(l+1)$$ where $l$ is an integer. If the molecule is a dipole it can emit or absorb electromagnetic radiation ...
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19 views

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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18 views

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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84 views

Why does inelastic X-ray scattering probe the longitudinal dielectric function as opposed to the transverse dielectric function?

Light is a transverse wave. Therefore, light in the optical range (i.e. visible light) couples to transverse collective excitations of a material when measuring the optical conductivity for instance. ...
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24 views

Spatial Resolution in Magnetocardiography

In the science paper called Development of an optical cardio-magnetometer by George Bison, it is mentioned that spatial resolution of 10-20mm is required for mapping MCG signal(page 52). What does the ...
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201 views

Intensive radiative heat transfer in very hot gas ( >5000K, gas core nuclear reactor related )

The question: At temperatures above ~5000K are not stable any solid or liquid materials or even more complex molecules (such as fullerenes and Polycyclic aromatic hydrocarbons) which emit/absorb ...
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198 views

Total angular momentum in multielectron atoms

I have some confusion about orbitals in multielectron atoms. Let's say we consider an atom (Lithium, for example, $1s^2\, 2p^1$) and that the state of the last electron is [n=2, l=1, ml=0, s=1/2, ...
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69 views

How to absorb a characteristic line in a spectrum

I have an x-ray tube. When I see the spectrum, I notice the characteristic lines of the anode. What do I have to do if I want to absorb a characteristic line? I have thought that I can add a filter. ...
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111 views

Correlation function in relaxation in NMR

I am new in this community, I am from a chemistry background. I want to know a detailed solution of a density matrix for a singlet state using the concept of spin lattice relaxation in NMR. I will ...
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129 views

Linewidth pressure broadening due to organic molecules

In relation to atmospheric spectroscopy and some other gaseous spectroscopy applications where organic molecules are present in the vapor, does anyone know of any papers or resources on pressure ...
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27 views

Selection rules in a finite quantum well

I have a finite quantum well made of two different semiconductors with different bandgaps and I want to calculate the different transitions between the energy levels possible that I calculated in that ...
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10 views

Spectral Signature

I am interested in studying about spectral signature of various materials. I am working as an electronics engineer intern in a company which deals with Hyperspectral imaging. Working with spectral ...
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15 views

Stark broadening and Voigt fitting

I have LIBS spectral data acquired with a CT spectrometer of resolution 0.4nm. I fitted the Voigt profile into the spectral peak at $\lambda_0$. The lorentz $\Delta \lambda_L$ and the gaussian ...
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62 views

Exact meaning of “pi/2 pulse”

In studying Mach-Zehnder and Ramsey interferometers, I came across the expression "$\pi/2$ pulse". What does it mean exactly? I am working with a Bloch vector representation $(u,v,w)$ of a 2 state ...
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25 views

Sum rule in X-ray Photoelectron Spectroscopy (XPS)

What is the sum rule in X-ray Photoelectron Spectroscopy (XPS)? how can I derive it? Can anybody explain the principle of sum rule in XPS or in spectroscopy in general? How can I apply it to a ...
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32 views

Multi-photon excitation probability for a two-level system

If a two-level system with a lifetime $\tau$ is excited with a pulse of duration $t_{pulse}$, what is the probability of exciting more than one photon? For simplicity we can take it to be a $\alpha ...
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33 views

Difference between three mutually complementary methods: Raman, Infra-red spectroscopy and inelastic incoherent neutron spectroscopy?

When I read the wiki on Raman spectroscopy, I found a paragraph explaining what system is suitable for using Raman and what others do not. It provide two other method as shown in title: infrared ...
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14 views

Gamma spectroscopy - Extractable information from peak significance changes?

Apologies for the title - I couldn't think of a better way to summarize my question I have a table which contains information on 60 gamma spectra taken over a total period of 20 days, from the hall ...
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44 views

Beta decay - Relative probability of electronic conversion for different disexcitations energies

I'm studying, experimentally, beta decay phenomena. Internal conversion of electrons happens when we have a sobreposition between a excited nucleus with it's electronic cloud. The colision between the ...