Ir Definition and 217 Threads

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...

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...

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. 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...

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...

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'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...

How can you determine the ratio of the keto tautomer of a compound to its enol form? I know which functional groups are associated with which but I have no idea how you'd use an IR spectrum for quantitative analysis like this.

Homework Statement A piece of solid Iron contains 2.5moles of atoms. Whats its mass? suppose one atom in 10^12 were missing one electron, what would be the net charge of the iron? Homework Equations The Attempt at a Solution atomic mass 192.22u so mass should be 2.5*192.22 =...

I keep seeing references to UV and IR in references to string theory and quantum gravity. This seems to come up in discussions of renormalization especially. Can someone please explicitly explain the term? Google doesn't seem to help here. There are way too many references. I have tried...

Unfortunately I have not been able to find anything reasonable online. I'd like an in depth all-inclusive explanation of IR transmitters and receivers, from a physical standpoint. I would also be glad to learn whatever else is included in the reading material, if anything. I have basic...

Hi, I'm trying to design a system which will be able to detect a hot object on a cold surface. The downside is the temperature difference is only 1 degree celcius and I'd like to use IR from a distance of about 10cm (further away preferred if possible). Does anyone with any experience of...

Quantum level working of IR sensor... There are datasheets of IR sensors like the TSOP1738 that conveniently tell me that when I make an IR LED flash at 38Khz, a current is produced. However, i would like to know what happens on an atomic level. Is it just a matter of electron promotion...

Say I want to monitor the interface of an electrochemical cell via IR spectroscopy. If H2 gas is generated, there must be a characteristic IR signature to this event. How can I figure out what this is? Are there calculations for this? I'm sure this is in the literature somewhere, but I...

Hi Why does a bond stretch or vibration have to cause a change in dipole moment to be IR active? Presumably all vibrational modes depend on energy aborption to occur whether they cause a change in dipole or not. I'm presuming that only those vibrational modes that cause a dipole change are...

My bedroom AC has a remote. I would like to make an ultra-simple circuit to duplicate just the ON button. I want to leave the real remote on the nightstand and still be able to turn my AC on from downstairs (I do have line-of-sight). I guess step 1 will be to detext what the remote is sending...

Hi Does anyone know why acetic anhydride has 2 IR bands at 1760 and 1820? If you look it up in a table it says they are due to the 2 carbonyl groups in an anhydride. But this is what I want to know: 1) What specifically is causing the peaks? Is it asymmetric stretching of the carbonyl...

My stereo remote has begun exhibiting strange behaviour. If I use the Power button to turn it on (or off), it will continue to do so for as much as 30 seconds. i.e.: - I point the remote at the stereo and press Power, stereo turns on (the on/off cycle on my stereo takes a good 4-5 seconds)...