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

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100 views

Molecular spectroscopy for atomic spectroscopers

My experience is with atomic spectroscopy of alkali atoms, I've recently been asked by a friend to help with some advice on analyzing molecular spectrophotometry data in the context of molecular ...
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184 views

Rutherford Scattering Spectra

I am using SimNRA to simulate the classical Rutherford Scattering. Playing around with it, I came across some spectra that I cannot explain... First of all, if someone plots the spectrum of ...
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1answer
118 views

Dividing two star spectra

I am doing some work that involves dividing two stellar spectra from the same star. Those stellar spectra are constructed by summing random samples of multiple spectra from the same star to improve ...
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2answers
336 views

How the spectrum of the hydrogen atom is checked/detected experimentally?

When solving the hydrogen atom, as a 2 body problem, we have the motion of the center of mass and the motion relative to the center of mass. The well known energy spectrum, $E_n$, that goes like ...
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27 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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34 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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32 views

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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48 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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11 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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21 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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94 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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1answer
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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14 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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35 views

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 ...
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1answer
218 views

Wigner Threshold law in Photodetachment and Photoionization

I am writing this question here because I have a problem in understanding the Wigner Threshold law in Photodetachment and Photoionization. The Wigner Threshold Law is given by: $\sigma$=$E^{L+1/2}$. ...
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64 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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16 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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1answer
117 views

Resolution in a Fourier transform spectroscopy setup

I am a bachelor physics student and as an assignment we had to perform measurements on an FT spectroscopy setup. Context. Our setup consisted of a Michelson interferometer through which the light ...
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1answer
26 views

Equivalent temperature: laser and cell containing Rb

What's the meaning of "equivalent temperature" related to a cell containing rubidium and crossed by laser?
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170 views

Why is an exciton only observed when we excite to the conduction band and not to other electronic level inside the bandgap?

Excitons can be observed when we excite electrons to the conduction band. I don't know about excitons being observed when we excite the electrons to an electronic level that would eventually be in ...
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146 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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146 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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616 views

What is the secondary electron cutoff in ultraviolet photoelectron spectroscopy?

While the fasted emitted electrons comes from the fermi level of the material in UPS measurement, where does the slowest, which is called secondary electron cut-off orginate from? I really can't ...
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65 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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1answer
108 views

Thermionic emission, delayed emission and predissociation

In molecular photodissociation, the thermionic emission, delayed emission and predissociation are the same? Otherwise, what is the difference between them? My question is not about the solids, but I ...
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101 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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2answers
175 views

Relationship of the abundance of an isotope and the vapor pressure

Say I have a sample of some alkali metal - Rubidium for example. A sample of Rubidium consists of approximately 27% $^{87}$Rb and 73% $^{85}$Rb. Does the vapor pressure of each isotope individual ...
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127 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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51 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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1answer
299 views

Spectroscopic notation $s$, $p$, $d$, $f$, $\ldots$

$s$ is sharp, $p$ for principal, $d$ for diffuse, $f$ for fundamental. Where do all those term come from? I do not see any link with the corresponding shapes.
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281 views

Precision measurements on sodium doublet wavelength?

I'm currently searching for a good and reliable source where precision measurements on the wavelength of the so called sodium doublet ($D_1$ and $D_2$ lines) at approximately 589.0 nm and 589.6 nm are ...
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2answers
41 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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1answer
33 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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2answers
48 views

For a planet which has a temperature gradient, hot in the center and cooler on the surface, why do we get absorption lines?

For a planet which has a temperature gradient, hot in the center and cooler on the surface, why do we see absorption lines? Similarly, why do we see emission lines if the planet is hot on the ...
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375 views

What is decay associated spectra?

What is decay associated spectra? Suppose we measure the fluorescence intensity over different wavelengths and over time, we get: $$I(\lambda,t) = \sum_i^n \alpha_i(\lambda) ...
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1answer
77 views

4 element super conductor without oxygen and iron

I am trying to find a list with super conductors. In particular I am searching for a superconductor, that consists of 4 elements none of which is Oxygen. The reason I rejected Oxygen, is because(from ...
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1answer
187 views

Diffraction Grating in spectrophotometer

In terms of spectrophotometer, we need to make the light monochromatic before passing it to sample. For that, we use diffraction grating. From the research, I found out that the grating reflects light ...
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1answer
237 views

Thermionic emission and delayed emission

I want to understand the concepts behind the thermionic emission. In thermionic emission, the energy randomization occurs and the energy may be split to electronic or roto-vibrational states. If this ...
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1answer
44 views

What's the difference between NMR and EPR?

Both NMR and EPR describe the response of magnetic spin to external field. When collecting data, how do you know you're looking at nucleus spin flip or electron spin flip? In other words, since every ...
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1answer
21 views

Spectroscopy - Absorption lines

Let's say we run a light source (a strong torch) with full spectrum light through a big, transparent, glass box filled with neon. Will we be able to see any Fraunhofer lines on the spectral analysis ...
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2answers
36 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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3answers
46 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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1answer
52 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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1answer
30 views

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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1answer
47 views

Nuclear explosion wavelength data

I am looking for data source (or chart) of spectral data that is being emitted on detonation of nuclear or thermonuclear explosion. Reason I am looking is to see if this data has specific signature ...
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1answer
161 views

Non Adiabatic Coupling Term in Born Oppenheimer Approximation

I am attaching a section from a text book (Conical Intersections Electronic Structure, dynamics and spectroscopy: David R Yarkony & Horst Koppel). Here I am not understanding the so called 'Non ...
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1answer
86 views

Where I could find values for rare earth metalls levels diagramm (Dieke diagram)?

The Dieke diagrams like this: could be easily found in internet. But it is impossible to determine from where they get values initially, everyone is making cross-links. I'm especially interested ...
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2answers
1k views

How to calculate the total angular momentum (J) values

How can I calculate the values of $J$ (total angular momentum) for a particular term, for instance, ${}^3P$?
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1answer
44 views

Is the temperature different and or salinity different can lead to different colour of the water bodies?

I had skimming on an article about Thermocline and Halocline. How can two seas not mix? However, I am still curious on: Why the effect of Thermocline and Halocline are distinguishable based on ...
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339 views

UV-VIS spectrometer on Solids

I ran an experiment using translucent single crystal solids. I modified the solids along the way using different chemical/temperature environments. After every stage, I ran the samples through a ...