Absorption Definition and 534 Threads

Homework Statement We have 2 laser beams counter propagating through a cavity with an atom traveling at some velocity. So one laser beam is propagating left and the other right. One laser beam has an intensity of .05*I_sat and the other 10*I_sat. The goal is to get the transmittance (or...

Hi, I have a student curious about amines absorbing CO2. He would like to construct a small demonstration capable of capturing CO2 with amines. He has also heard that electric shock is able to release the CO2 from the amines and would like to see this as well. There are few things puzzling me...

EXPERIMENT ABSORPTION OF γ - RADIATION IN LEAD AND CALCULATION OF ABSORPTION COEFFICIENT µ Using equation (3) / slope of graph lnC vs d - estimate µ. This should be in units of per meter (m-1 ). The formula in the analysis are as follows : 1. I = I0 e-μd 2. C(d) = C0 e-μd 3. lnC = lnC0...

Why can't hydrogen gas on the stars be detected by using line emission spectrum of hydrogen. Why must we use line absorption spectrum to detect?

Does phonon required a minimum energy in the absorption process of an indirect band gap, and why?

Hi all, Whew, last question for a while: I think I already know the answer, but want to confirm (e..g, I think this thread basically answers the question, https://www.physicsforums.com/threads/propagation-of-wavefunction.152053/) As an example, let's say I have an electron (in free space or...

I recently bought a cheap and cheerful hand held spectroscope. Great fun to look at CFL lamps and the modern LEDs. Those LEDs are really good, btw. Also, the 'scope gives a pretty even spread of brightness over the whole visible range. (an equipment check). I have been looking at the spectrum of...

Is to possible to provide cooling for automobiles using vapor absorption compression system utilizing the exhaust gases? If possible how efficient can this method work?

What is the nature of the randomity that results in where a photon is absorbed? I'm thinking of the double slit experiment with single photon emmisions. There is the greatest probability of absorption in the middle reagon, but despite that the photon sometimes goes to one of the far sides. What...

When you heat things up, they emit specific wavelengths of light, right? Like when you heat up sodium, it emits yellow. But don't things emit shorter wavelengths of light at higher temperatures? Like how hotter stars are blue and colder stars are yellow. Since stars are mostly hydrogen...

Hi Guys I´m studying the absorption and emission phenomena of a gas and, according to Kirchhoff "extended" law, for a body at thermodynamic equilibrium, the following statement is true. ελ(T,θ,φ) = Aλ(T, θ,φ). So, if i understood correctly the meaning of this equation, The amount of absorbed...

So I just learned that in a spectrum like this one: (For now, let's concentrate on the graph given below.) The longer the dip is in the graph, the more the corresponding element is present. However, if each individual color corresponds to a different element, then how can a larger dip mean...

Let's consider a two state quantum system in which an electron is either in the ground state or in the excited state with the energy difference E. We know that if we put this system in a monochromatic electromagnetic field (with frequency E/h) the electron can become excited by means of...

Hello Forum, What does the process of two-photon absorption photon entail? That, in general, a molecule or atom (composed of many electrons) that is illuminated by an electromagnetic field can only absorb one photon at a time except in those special cases where two photons can be absorbed...

Greetings, Is there a difference between reflection of radiation and emission after absorption? What causes this difference? Another related question: According to wikipedia: "Earth's surface and the clouds absorb visible and invisible radiation from the sun and re-emit much of the energy as...

We know that molecules absorb light based on their electronical, rotational, and vibrational transitions and the governed transition rules (so that each molecule has its own "fingerprints"). But I do not know why it happens? Lets simplify it a little: A methane molecule, for example, is...

Homework Statement Hello, I have a bunch of UV-Vis spectra to analyze and I am having a hard time choosing what the "onset" of each spectrum is, which I will use to calculate the optical band gap of each spectrum. Homework EquationsThe Attempt at a Solution I read somewhere that plotting...

Can the Kerr effect have a effect on absorption, and transmission, of the electron.? Also is there any way to make electrons move to higher shell levels, without the electrons getting excited by light, and moving to higher Shell's. Or is light absorption the only way for electrons to move to...

who was the first person to discover how to measure the wavelength of absorption lines in the solar or stellar spectra and what method was used?

... transmission of any electromagnetic radiation. I am trying to think of a way for em waves to pass through a solid opaque material, and then while the em waves are INSIDE the material, then some how the electrons absorb the em waves. Any em waves that get absorbed by electrons like light...

In my education of QM, I've heard countless times how energy is quantized by Planck's Constant, and how radiation is only emitted and absorbed in these discrete steps. Recently I've heard that that's not the full picture of energy, and I was hoping you could draw some clarity for me. In...

hi pf nice to see you. I have a question about optical absorption spectrum of nanoscale substrates. To get an absorption spectrum of nanostrucutred material, I want to perform both fdtd calculation and optical simulation. When I do fdtd calculation, I set the incident light illuminated with...

hi every one can you tell me how to calculate the absorption coefficient of a thin film using the absorption and the transmittance spectrum plotted as a function of the wavelength (knowing that i don't know the thickness of the film )

Homework Statement Hello, This week I ran an AA Spectroscopy experiment in my university, in which we had to analyze the percentage of Copper in a metal coin, and the containment of Iron in morning cereal. We used 2 standard solutions of 1 and 10 ppm (containing both Copper and Iron), and...

Homework Statement A solution of Co+2 ions appears red when viewed under white light. Which of the following statements is true? A) a spectrophotometer set to the wavelength of red light would read a high absorbance b) if the solution is diluted, the amount of light reflected by the solution...

Anyone can explain me this example? I substitute value for e = 1.602*10-19; m0 = 9.1*10-31; pi = 3.14; and calculated value for μav in matlab. I received 1.7104*10-19. But in exam this value is 0.68*10-25. What is i wrong? please help me. Thank you.

Homework Statement I could not fit the whole problem typed out but; Describe with a diagram, an absorption experiment to distingush between alpha, beta and gamma radiation. Homework Equations None required, written question. The Attempt at a Solution Source, absorbers placed in front of...

Homework Statement N2 molecules absorb ultraviolet light, but not visible light. I2 molecules absorb both visible and ultraviolet light. Which of the following statements explains the observations? a) More energy is required to make N2 molecules vibrate than is required to make I2 molecs...

Hi everyone, I am interested how is polarized light absorbed by a molecule or an atom. Unfortunately, I come to a problem in the derivation where a complex vector in a real space appears. This is something I never seen before and I do not know how to interpret it. Therefore I would like to ask...

i would like to know the self absorption parameter of 3x3 inches NaI crystal. which is used in estim,ating the radionuclides

Can an electron absorb a photon and jump to a higher orbit if the next level is already full of electrons? please explain what happens and also link info that might help me with electron/ photon interaction. I have many questions. Thanks

-ion process. The electron when hit by light moves to a higher shell level very briefly, to either shell 1, or 2 depending on the energy of the light wavelength. So because you mixed any EM radiation, with red light which has the lowest energy, could when light, or other EM waves gets absorbed...

In griffith's introduction to electrodynamics, he goes over dispersion/absorption using the oscillating electron model. I understand the theory but I am confused about how it relates to how materials appear to us. He says that the material will be practically opaque in the frequency range with...

My name is Nicholas Lee, and I am studying neuroscience, and I am trying to find a way to find better ways in neuroimaging, and microscopy to see the brain better, to find better cure for Parkinson's disease, and Alzheimer's, and epilepsy If you have a four inch cubic block of glass, and carbon...

Hello, I have some papers (I can give references if needed) giving the oscillator strength of rare gases for a given energy bandwidth and from those values, I would like to calculate their absorption in those bandwidth. However, I am a little bit lost in how to do it. I looked a bit around and...

Hey Guys. If an absorption line of hydrogen was observed in the spectrum of the Galaxy, and it's wavelength was 494.9nm, and then the same line was found to be 490nm in the laboratory (in orbit around Earth), what could be drawn from that? Thanks, Atominate

Transition of an electron from the valence to conduction bands (direct transition at a k-point near the band edge) would change the momentum of electron because the sign of the group velocity in valence and conduction bands are opposite. Could one infer that the direction of radiation is a...

Homework Statement Aluminium (Ar = 26.98, ρ = 2700 kg/m3) has cross-section of thermal neutron absorption 0.23 barn. What is the absorption length of thermal neutrons in the aluminium? What value decreases neutron intensity in 0.6 mm, 8 mm and 80 mm aluminium? Homework Equations Beer-Lambert...

I'm measuring transmittance through and reflectance from thick glass samples, using spectrophotometers. Does anyone know if there's an exact solution for the surface transmittance r, surface reflectance t, and absorption coefficient A (as in Beer-Lamberts law). For a specific wavelength the...

Hi,I have a question when I was reading this website: http://www.webexhibits.org/causesofcolor/7F.html It explains how melanin works to protect us against UV light. From high school physics course we know that black absorbs light while white reflects. I understand when melanin accumulates,more...

Hi, everyone! I was thinking about atomic absorption/emission of photons and how they all have specific locations in the frequency zones as "lines" of missing/peak emissions. I'm curious if there is a scientifically proven/hypothesis of how the physical oscillation of atoms in molecules due to...

Hi, After a course on refrigeration and air con over the summer I'm looking for a subject to study for a dissertation next year. From the course I'm very interested in absorption refrigeration as it could have great potential for less economically developed countries and refugee camps. I've...

Homework Statement A slab of glass 0.5 m thick absorbs 50% of light passing through it. Compute how thick of a slab of identical glass you would need that: - absorbs 90% of light - absorbs 99% of light - absorbs 99.9% of light Homework Equations I spent an hour looking for formulas in my...

I'm curious, why does Helium-3 fission into H-3 and H upon neutron absorption? Surely the He-4 nucleus configuration is more stable? I get that the energy release may be what splits the nucleus, because it releases quite a lot of energy if it were to simply absorb the neutron.

Hi pf. As I understand we know what a star is made of by looking at the absorption spectrum from a star. Since a star is a black-body it gives out a continuous spectrum of light but as this light passes through the Sun's atmosphere, certain wavelengths are absorbed depending on what the star is...

Am I correct to assume that drugs taken orally work by being absorbed by the intestines? I might have a parasite & was wondering if their presence can weaken drug absorption? After all, parasites can weaken the intestines' ability to absorb nutrients so why wouldn't the same go for drugs...

The fact that energy in a laser can propagate without much loss over long distances is quite shocking ! It's a renowned fact that energy is dissipated when propagation takes place through any medium... (I'm fully aware that laser is an exception) But I have quite a difficult time understanding...

Hi, I have some modelling code that uses data from Hitran 2012 (https://www.cfa.harvard.edu/hitran/Download/HITRAN2012.pdf). I want to use some data from Lifbase but unfortunately the absorption coefficient units do not match. Lifbase units are given in m3 J-1 s-2 whereas Hitran units are...

Hello chaps, I'm trying to calculate absorption coefficients of gases at moderate temperatures ie ranges in which diatomic gases (such as N2 orO2) are partially disassociated or ionised, therefore including molecular bands as well as continuum. Can anyone recommend some suitable reading...

How can I calculate the absorption cross section of a harmonic oscillator in an EM field?