What is Spectroscopy: Definition and 332 Discussions
Spectroscopy is the study of the interaction between matter and electromagnetic radiation as a function of the wavelength or frequency of the radiation. In simpler terms, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum; indeed, historically, spectroscopy originated as the study of the wavelength dependence of the absorption by gas phase matter of visible light dispersed by a prism. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associated with a spectral signature in the context of the Laser Interferometer Gravitational-Wave Observatory (LIGO).
Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of physics, chemistry, and astronomy, allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, molecular and macro scale, and over astronomical distances. Important applications arise from biomedical spectroscopy in the areas of tissue analysis and medical imaging.
How can astronomers use earth-based spectroscopy to determine the chemical composition of nebulae, stars, planets etc. when the light has to pass through the Earth's atmosphere before it's detected? Does the chemical composition of the Earth's atmosphere pose a problem?
Homework Statement
if light incident on a grating makes an angle phi with the normal of the grating, show that the equation m(lambda)=d(sin(theta)) becomes m(lambda)=d[sin(theta-phi)+sin(phi)]
Homework Equations
m(lambda)=d(sin(theta)) d=spacing of slits, theta=angle displaced from...
From uncertainty relationship ∆E τ ~ hbar, what is the lifetime for a state that gives rise to a line of width 0.1 cm^-1? what about for 100 MHz?
How do you get the energy term? I'm really not sure how to do this, would appreciate some insight, thnx.
Hello
I am looking for a few textbooks to digest, I am learning the fundamentals of spectroscopy, in particular absorption spectroscopy of gases. Are there any great textbooks out there on these subjects? I feel I need a more solid grounding.
Any undergrad would be welcome, as would any...
Hey everyone,
Over the past few days I have been having trouble with finding research for my optics project.
The topic I chose was supposed to be the physics behind how astronomer's and astrophysics measure the Spectrum of the Sun ans specifically the mathematics/physics behind the...
Hello, I am having a little trouble getting to the fundamentals of FM (laser) spectroscopy. As I understand from some research, the frequency of the incident beam is varied with a second frequency much larger than the first:
Bjorklund 1980: "The key concept is that the modulator is driven at...
All of my questions that follow revolve around the question of atomic geometry/structure as it relates to quantum mechanics.
On every high resolution (1 angstrom, and a few less than 1 angstrom) TEM image I have seen, atoms appear as spheres. I then found a website that claims it has visualized...
Hi,
I have measured some spectrums from various gamma sources and I was wondering what kind of fitting I should do to determine the Compton edge. I have access to Logger Pro, Excel, and mathematica. I have fit the photopeak with a Gaussian so I know the uncertainty in the Compton edge, I...
Quoting from wikipedia
I understand what symmetrical and antisymmetrical stretching come from and the number of vibrational mode(s) can be predicted basing on the concept of degree of freedom.
However, for scissoring, rocking, wagging and twisting, are they considered as bending...
Hello,
i ve got some questions on spectroscopy. surface states and quantum well states have free-electron like dispersions, they a more or less free states, so E ≈ k*k. d-electrons have flat dispersions, they are bound. My Question is: why have bound states flat dispersions? does this have...
I am taking my second semester of organic this summer. We are working on IR Spectroscopy and mass spectrometry in class. Is there anywhere that anyone knows about that may put it all together? Or can anyone maybe give me some tips on how to remember all of the main functional groups? I am...
i need help in determining thickness of thin film created by pouring volatime solvent with solute using HATR technique also would like to know how experimental design can be set with HATR technique quantification purpose.
hi
i m studing AAS(atomic absorption specvtroscopy) technique.using beer"s law i plot a graph bw absorbance and concentration.then how can i make the quantitative analysis of my sample?
Hey guys,
There is something I have known and applied for a long time, that the greater the length of an interferogram the greater the resolution of the resulting frequency-domain spectrum. But I've never fully understood why, I've always waved it off as something to do with the uncertainty...
Apologies for making a long posts, I just wanted to lay down the basic idea of what I'm doing at the beginning.
I'm working on a home-made Michaelson type Interferometer. I'm trying to make few changes, mainly modulation of the black-body type radiation (Globar).
Instead of amplitude...
I did a bit of x-ray spectroscopy in labs studying Fluorescence of some different elements. I was just wondering whether or not flourescence occurs in all elements?
I'm sure I've read people talking about 'flourescecnt materials' or something like that.
I can't think of any reason why it...
I'm a freshman physics major and I'm doing summer research on Raman Spectroscopy. I've read up on it a bit but I was wondering if there are any resources that would help me better understand or at least get a general idea of what this is.
In rotational (microwave) spectroscopy, the Kth energy level is BK(K + 1), B = constant.
It turns out the each Kth level is (2K + 1) degenerate.
Now, as the energy level increases, does this mean that a single molecule will be in all these states at once, or in one of them? Or does it...
Homework Statement
I have attached the IR and NMR spectrum from lab. I have determined that there was a nitrogen present in the compound. There was no sulfur or halogens. The molecular weight was 138. The compound was solid and yellow color. It had a melting point between 124 and 134 C...
I wonder if anyone have an idea about the software (CASA) used for the treatement of data dounded by XPS analysis. If yes, I am in need to know how to remove the satellite peaks that may show in a spectrum.
thanks
Hi,
Does anyone know any good Linux/Unix software for analysing optical emission spectra? I've been searching the net, but I can't find any. The software I'm currently using is old, only for MS Windows, very expensive, and pretty much useless.
So any suggestions would be much appreciated...
hi friends,
I'm going to simulate the spectrum of a specific ion, with constant situation (like: density, temperature and etc).
but I don't know what should I do first!
thanks for your help
:frown::yuck:
I've got the spectra for C5H8O2 (the spectral database confirms that it's ethyl acrylate) and treatment with hot aq. HCL causes the signals in the 1N NMR spectrum at d 1.3 and 4.2 to disappear. Does anyone know why this happens? Thanks!
I know that theorically the numbers of counts between compton edge and the photopeak must be zero. In practice it doens't occur. Why?
Thanks in advance!
Are the results of Atomic Absorption Spectroscopy affected if the metal were ions? For example, if you were trying to measure the amount of zinc in a sample but part of it was dissolved as ions and other parts were simply solid, would they measure the same absorption or would the ions not be...
Homework Statement
Hey people, I'm in dire need of help for this question.
Say you are given a list of wavenumbers (eg. 80, 90, 100, 110 cm^-1) for rotational transitions, and you are asked to assign rotational quantum numbers J to the transitions, how would you do that?
Homework...
Homework Statement
Calculate the energy and radius for each of the five lowest (n = 1,2,3,4,5) electron orbits in a Helium atom with only one electron. Enter the energy as a positive value in units of "eV" and the radius in units of "nm". Hint: The Helium nucleus has 2 protons so Z = 2 and...
Homework Statement
Light in the near-infrared (close to visible red) can penetrate surprisingly far through human tissue, a fact that is being used to "illuminate" the interior of the brain in a noninvasve technique known as near-infrared spectroscopy (NIRS). In this procedure an optical...
Homework Statement
I just want to know if there is a relationship between the ground state of Hydrogen which is 13.6 eV and the ground state of Helium. The problem is asking me to find the ground state of Helium, but I am not sure how to go about it. Any advice?
Homework Equations...
Homework Statement
I have a 3 compounds with the same formula: C6H12O2
I need to find the molecules by interpreting the H NMR spectroscopy
http://aceorganic.pearsoncmg.com/epoch-plugin/tempfiles/1867_430.jpg
http://aceorganic.pearsoncmg.com/epoch-plugin/tempfiles/1869_524.jpg...
Raman spectroscopy of protein please help
Hey any Raman experts out there?
Im doing Raman spectroscopy of a protein called c-reactive protein (in aquous solution) using 532nm 10mW and the protein placed in a nmr tube. I can nicely get a spectrum of benzene and cyclohexane, but when I am doing...
I read in a journal article that in raman spectroscopy "it is well
known that signal yield increases with shorter wavelength". Can anyone please explain why? I would've thought longer wavelengths = shorter frequencies = higher susceptibilities?
I'm trying to comprehend a paper I'm supposed to summarize
this one:
---ok it won't let me post urls---- whatever
My question, is what is the deal with photoinduced absorption spectroscopy? I gathered that it involves a "pump" (burst of light) striking the sample and then a "probe"...
Hello there. I have a small problem trying to calculate the resolution of a DFTS (Dispersive Fourier Transform Spectroscopy), which is very similar to Michalson Interferometer or FTS (Fourier Transform Interferometer). I know it has something to do with the scanning distance of the delay arm and...
Hi,
I have designed and built my own impedance spectroscopy instrument, using a lock-in amplifier approach, with a reference signal. I know the basic theory behind impedance and impedance spectroscopy. However, I would like some thoughts on experimental set-up.
I have a reference source...
Hi
I'm trying to measure the concentration of a sample dissolved in water. I'm using the spectrometer USB4000 which directly gives me the absorbance value. Using beer-lambert law is there a way i can determine the unknown sample concentration from this measurement? I have the values 'A' and...
I've been trying this for 3 hours and I'm getting nowhere. These are the graphs I made for Hydrogen Intensity vs Frequency for a radio telescope that transits the sun and galactic arms of the galaxy.
http://img220.imageshack.us/img220/5904/helpgraphia6.jpg...
Hi Everyone,
I am giving a talk on group theory as related to spectroscopy (IR & Raman) and I was curious about how to explain the jump from knowing which modes in the charcter table are Raman active to predicting what kind of vibration they will have. For example the Td point group has raman...
Homework Statement
For a many electron system with L=2,S=1 and J=2 calculate the angle between the L and S vectors both according to the old quantum theory and quantum mechanics.
Homework Equations
The Attempt at a Solution
I suppose this problem is nothing but a simple application...
I have a take home quiz here and it would be greatly appreciated if someone could check over my work (it's numeric response btw):
1) A singly charged lithium ion (m= 1.16x10^-26 kg) is accelerated from rest thru a potential difference of 5.60 x 10^5 V. The velocity selector consists of an...
I referred to hyperphysics to learn that for electric dipole transition,the selection rules are
\Delta\ l =\ 1
Or, \Delta\ l =\ -1
And, \Delta\ m_l =\ 0
Does not it include n transition?
How is n transition different from transition among the orbitals?
I mean n transition...
Is there a way to measure the atomic number of a source using gamma spectroscopy? Like, I know that if you have different back scattering material, it will produced different intensity backscattering peaks, but is there a formula that relates intensity of backscattered peaks to the atomic number?
I have done a few Spectroscopy questions already, However I am having troble with these last three problems. Any help would be GREAT!
Here is the link tothe spectroscopy questions.
On worksheet 6b, I need help on #1 and #2.
On worksheet 6a I need help on #4...
please reference the link here
This is the gamma spectrum for Co-60 from the wikipedia site:http://en.wikipedia.org/wiki/Gamma_spectroscopy
though wikipedia might not be the best of sources, I was just wondering a few things. The two peaks around channel 700 and 800 are referred to as a...
Hi,
I wanted to know that whether my following experiment is conceptually correct or not.
I am making a project on spectrosopy. And I have created my files and chart and everything the only thing which is left is a working model.
Now what i am trying to do is to find out the...
Hi
I have decided to make my chemistry project on spectroscopy. I have included optical spectroscopy,Molecular spectroscopy,Resonance spectroscopy and X ray spectroscopy. Molecular spectroscopy includes microwave,raman,visible,stark,photoelectron and etc
I am in the 11th standard ie 16...
[SOLVED] Sites with IR, 1H NMR, 13C NMR, and mass spectroscopy?
I was wondering if anyone knew where I can look at IR, 1H NMR, 13C NMR, and mass spectroscopy (sites or programs). I'd like to be able to input the name of an organic compound and be able to see these spectra. Thanks.