Ir Definition and 229 Threads

My IR spectra correlation chart for organic chemistry says that the stretch for a nitro N-O bond occurs at "1550 and 1400cm-1" and that it will look like "teeth". Why does N-O have two peaks? The rest of the functional groups on my chart list a range in which a single peak should appear, but why...

Homework Statement Hi. I'm starting to read about IR spectroscopy and I have a question. I know that there are 2 kinds of vibrational modes in molecules: bending and stretching, so in a molecule like water for example, how can I tell which one of the vibrational does it have? What I mean...

Hi, I've been reading that in a relatively normal environment about 1/2 of human heat loss is due to radiation. Most of this seems to have a wavelength of 10-12 μm. Could someone here speak to the molecular origin of this? I'm guessing it is mostly from water molecules going from a higher...

Hi there. First time PF poster. I have a question about interpreting IR spectro graphs. I get the general idea of interpreting the sharpness and strength of the line but when I need to ID the pulse down I have to choose between \delta and \upsilon (or mabe its just v) version of the...

I scanned 2 different compounds (Glucosamine HCl and Glucosamine Sulfate 2KCl) using an FTIR with ATR and their spectra were identical :confused:. Where would the peaks of a sulfate group appear in the IR?

I read that bond vibrations are only IR active if they produce a change in dipole moment. I'm trying to visualise how this works with chromium hexacarbonyl: If I'm not mistaken, this compound has one significant IR absorption at around 1900 cm-1, which is a C-O stretching absorption. Is this...

Hi I am trying to get my head around Emissivity and was wondering if anyone could help. There is a "blackbody" with emissivity of 0.97. We want to use it to see whether some IR thermometers are giving suitable readings. Unfortunately the emissivity of the thermometer is unknown and...

Hi @ all, I have a question about IR divergences at hadron colliders. I can see that there are also IR divergences in loop diagrams such as the vertex correction and so on... I also see the IR ones in the real gluon/quark/ or photon emission... so that for example the gluon is soft or...

I made some frequency calculations in Gaussian (using various method/basis set combos) and I have to find which method/basis set combo is the most accurate by comparing the results to literature values. I got the calculated wavenumbers along with their intensities but my professor tells me I...

I've developed a new concept called "Ambient Light Ignoring Infrared Active Distance Sensor". It consists of a transmitter with an infrared LED which uses a traditional LM555 timer to oscillate a frequency of 5kHz and a modified receiver which consists of a common emitter setup, NPN...

I have a hand held night vision scope (Russian made I suspect.) Came with a small Solid State IR "lamp." The IR source is separate and battery powered. It has a built in hand operated charger that you squeeze several times and it will hold a "charge" on the sensor for a while and then...

Hello all, I'm currently using an infrared camera to determine the emissivity of a steel. The camera "sees" whatever radiation entering the objective, and calculates the temperature of the steel by assuming it's emissivity is 1. I figured I could use an energy balance to find the emissivity...

I work in a nano-optics group, and need an IR thermometer with certain specifications. Online I have only come across cooking thermometers and industrial thermometers, so I need help finding one for a physics experimental lab setup. Specifications: - high accuracy, and pin-point surface...

Can a lux meter measure infrared intensity like it does for the visible light? I read from somewhere that it cannot. If you have an IR illuminator on in the dark and hold up your 'regular' lux meter to it, it will likely register 0 - an unhelpful and misleading result. I'm just wondering if...

My question is about using an IR thermometer for measuring the temprature of a blackbody that emitts a spectrum that peaks somewhere in the visible region. I think since these kind of thermometers measures the amount of infrared radiation emitted by the object, they can only determine the...

Any ideas? Thanks so much!

Hi All, My first post here. As far as I've understood there are problems with massless states in two dimensions. In the problem I am working on I have a 2D (non linear) sigma model with a lot of symmetries. The worldsheet fields come as heavy and massless. My main interest is to...

Hi. I am working on visualization of flow with thermal infrared camera. As it is known, water is not transparent for IR spectrum of light, so you can`t watch phenomena that are occurring "inside". You can only see things that are occurring on the interface of water and wall. I have been...

Alright, here is what I'm coming up with: we all know that most IR remote, if not all IR remotes works by the "lights on/lights-off" "principle", be the actual implementation “measuring” interval or space between 2 "ons" (or two offs), or demodulating one consistent on (or off) for a specific...

I'm building a small project and would like some assistance from you folks. I have this motor 5rpm -12vdc and I'm using a Class 2 plug in transformer (input 12VDC 60Hz 23W - output 12VDC 1000mA) to power it up. I would like to add a IR LED/Phototransistor between the two to act as a on off...

We have recently (Oct) fitted 7 IR heaters which use triac based controllers. There have been any number of problems with the controllers and IR halogen elements failing. The supplier has now suggested that we may have interference or spikes on our mains supply which they claim may affect or...

hello i was just wondering what is considered to be the finger print region in an IR spectrum. Is there a range of wavenumbers which are designated as the finger print region? ...let me clarify um so a C-O bond in an ether (and maybe alcohol) is suppose to have a peak in the 1000-1200cm^-1...

Homework Statement This is for a lab report I'm trying to write. I need to figure out what the effect of different coordinations of a manganese carbonyl complex should be on the frequency of the carbonyl stretch in my IR spectrum. Homework Equations There are 4 complexes: Mn(Br)(CO)5...

I am designing a game where you would shoot an IR gun at an object that would turn a light on and stay on until manually reset. I don't know much about electronics and any help would be appreciated.

Please teach me this: The UV divergence problems are solved by Renormalization Procedure,but I do not understand how to solve IR divergence problems. Thank you very much for your kind helping.

This is a very silly question but anyway. When using a remote for a TV or digital channel receiver, how big is the path/signal emitted from the remote when a button is pushed. Will it come from a point, thee emitter, and form a cone shape until its picked up by the receiver. its a dull...

Homework Statement I have attached the question and necessary infromationHomework Equations The Attempt at a Solution so here's what I would say "Unlikely as the peaks in the IR spec are very similar, no additional peaks have shown" BUT THE MARK SCHEME SAYS Vanillin IS likely to have...

Lets say I need to predict the number of infrared absorbance peaks that will appear on the IR spectrum of a given molecule. As an example, I'll use this molecule: I can see that the point group of this molecule is C4v. I can look up this point groups character table...

Homework Statement Would anyone be able to tell me if I'm on the right track with determining the peaks on these NMR spectrums? We had to synthesize a product of Chalcone and then hydrogenate it to obtain an unknown product that we have to correctly identify. This had been quite a difficult...

Hi everyone I am an amateur modeler and am very interested in physics and am trying to to make a model car/roadway that can move and be controlled by a computer. I have managed to placing a motor in the models, but have not found battery's which are small enough and can run it. So what i...

IR Detector Question... If someone take an IR sensor and puts a red covered piece of plastic over the sensor...is that really going to significantly affect the performance? A friend of mine has a laser detector for road use and it appears to have a red plastic cover over the IR sensor...

After you find the irreducible representation of a molecule, how do you determine the number of IR active bands? For example, in methane, the pointgroup is Td , then you found that the irreducible representation is A1 + T2. How do you find the number of IR active and Raman active bands...

According to my understand of what makes something transparent, it's because a given wavelength of light doesn't have sufficient energy to raise the electrons in a material to a higher energy level, so the photons are not absorbed and continue on. This explains why glass is transparent for...

Hello All My company has several products that use an IR emitter & receiver in line and are used as a sensor to detect when something 'breaks the beam'. The problem we are running into is that several of these components are aging prematurely, but they work perfectly at the time of our...

hi , every body here , I really seek a help , I have an Ir led from thorlaps it's wave length 1450 nm , I followed the specs Forward voltage at 20mA is = 1.2 v typical , 1.5 v Max Max DC forward current = 100mA Power dissipation is 120 mW I tried the following resistance 200 ,220 ,190,180...

was just wondering... Do IR thermometers measure the temperature of an object via the intensity or wavelengths of emitted light? I've heard that you can measure the temperature of clouds with them, why doesn't the IR light emitted by the air in between the cloud and the detector confuse...

I'm confused about what is going on theoretically with Raman, and light in general, wrt photon absorption, annihilation, and re-emission; I don't have the math background to understand Fourier transform, of anything past simple algebra anymore, but would like to at least have a decent...

I've been doing IR spectroscopy to examine to the absorption spectrum of water and carbon dioxide, after which I took another absorption spectrum with a methane gas cell. The absorption spectrum without the methane shows absorption from carbon dioxide around 4000nm, however, this is not apparent...

Hello, i have a college seminar due 1 week from today and our group has already done the writing part of it, but now we need to take a few pictures with the IR camera itself and we are clueless what to actually shoot because the idea must be innovative and simple and must be backed up by heat...

One of my high school students recently demonstrated that the camera in an Android will detect the IR signal of a remote control, but the camera in an iPhone will not. (I understand that screening out IR is desirable in photography, and the distinction is arguably a matter of camera or filter...

Hi I'm taking part in a robotics contest and that requires my robot to reach the desired destination using line tracking. The line to be tracked is made of white tape. Now I'm in a sort of dilemma here. I was in favour of using IR sensors to track my line and through experimentation I...

Hi guys, my first post on these forums. I am learning electronics and am still very new to this all. My current tinker project is to learn how regular tv remote controls work. So far I have understood that the remote sends blinking IR pulses through an 940 nm LED. The remote uses...

i had a discussion with a physicist i proposed that in order to avoid the IR divergence \int_{0}^{\infty}dx(x-a)^{-3}x^{2} we could propose as regularized value the value of F(-a) , where F is the integral \int_{0}^{\infty}dx(x+b)^{-3}x^{2} so if we could regularize this simply...

So I'm doing research on a particular protein and I need to find bond lengths to parameterize the chromophore. I currently have a bunch of IR Spectroscopic data and I'm thinking I can use the wavelengths of absorptions between bonds to somehow find bond length. I am actually a physicist and so...

Hi guys, this is to make something for a uni project I'm doing, not asking for the answers to a homework-type problem so I wasn't sure if it should go in the homework section, but if you think it should let me know and I will move it. So the project background is a timing system for solar...

since the strings are no longer points, the UV divergences are avoided from calculations, but what happens with IR divergences ? ,

I have a project in mind that I need help with IR LEDs. I'm not an electricity expert; actually, I have almost no experience in electronics. I had an idea for a project and now I'm just trying to make it work. I will need to power a number of IR LEDs at one time for a continuous period. Is...

http://arxiv.org/abs/1012.4216 4-dimensional Spin-foam Model with Quantum Lorentz Group Muxin Han 22 pages, 3 figures (Submitted on 19 Dec 2010) "We study the quantum group deformation of the Lorentzian EPRL spin-foam model. The construction uses the harmonic analysis on the quantum Lorentz...

Does anyone know the ISBN of a good textbook that goes into VERY deep details to build a zoom capable IR scope. Also the scope would have to give contrast such as show trees and other things that don't give off IR so that you are not just viewing a silouette of something in a blank frame.

Hello, Is there such a thing as a projection screen that is transparent to IR? I need to project an image onto a screen (rear-projection), but I also need to send an IR signal through the screen from the side of the human user back to the side with the projector. I think there are...