Well, docstoc was a bust.......meanwhile....
googled: "mechanism of IR absorption"
http://elchem.kaist.ac.kr/vt/chem-ed/spec/vib/ir.htmIR spectroscopy is the measurement of the wavelength and intensity of the absorption of mid-infrared light by a sample. Mid-infrared light (2.5 - 50 µm, 4000 - 200 cm-1) is energetic enough to excite molecular vibrations to higher energy levels. The wavelength of IR absorption bands are characteristic of specific types of chemical bonds, and IR spectroscopy finds its greatest utility for identification of organic and organometallic molecules.
The result is that there must be a change in dipole moment during the vibration for a molecule to absorb infrared radiation.
Examples of infrared active and inactive absorption bands in CO2
...
http://www.infochembio.ethz.ch/links/en/spectrosc_ir_lehr.htmlhttp://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/InfraRed/infrared.htm#ir1
Photon energies associated with this part of the infrared (from 1 to 15 kcal/mole) are not large enough to excite electrons, but may induce vibrational excitation of covalently bonded atoms and groups. The covalent bonds in molecules are not rigid sticks or rods, such as found in molecular model kits, but are more like stiff springs that can be stretched and bent. The mobile nature of organic molecules was noted in the chapter concerning conformational isomers. We must now recognize that, in addition to the facile rotation of groups about single bonds, molecules experience a wide variety of vibrational motions, characteristic of their component atoms. Consequently, virtually all organic compounds will absorb infrared radiation that corresponds in energy to these vibrations. Infrared spectrometers, similar in principle to the UV-Visible spectrometer described elsewhere, permit chemists to obtain absorption spectra of compounds that are a unique reflection of their molecular structure.
Infrared spectra may be obtained from samples in all phases (liquid, solid and gaseous). Liquids are usually examined as a thin film sandwiched between two polished salt plates (note that glass absorbs infrared radiation, whereas NaCl is transparent).
A molecule composed of n-atoms has 3n degrees of freedom, six of which are translations and rotations of the molecule itself. This leaves 3n-6 degrees of vibrational freedom (3n-5 if the molecule is linear). Vibrational modes are often given descriptive names, such as stretching, bending, scissoring, rocking and twisting.
Some General Trends:
i) Stretching frequencies are higher than corresponding bending frequencies. (It is easier to bend a bond than to stretch or compress it.)
ii) Bonds to hydrogen have higher stretching frequencies than those to heavier atoms.
iii) Triple bonds have higher stretching frequencies than corresponding double bonds, which in turn have higher frequencies than single bonds. (Except for bonds to hydrogen).
...
http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/spectro.htm#contnt
http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/InfraRed/infrared.htm#ir1
Very neat little "Frequency - Wavelength Converter"
...
http://www.pslc.ws/macrog/irabs.htmO-C-O scissors 645 - 575
...
http://www.google.com/search?hl=en&q=%22CO2+translational+vibrations%22&btnG=Search
TRANSLATION TO VIBRATION TRANSITION PROBABILITIES IN CO2-H2 AND ...The probability of a collision transferring energy from translation to vibration generally increases with relative speeds with which the molecules collide.
stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0635097 - 5k -
http://stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0635097Abstract : The probability of a collision transferring energy from translation to vibration generally increases with relative speeds with which the molecules collide. Measured transition probabilities, therefore, generally increase with temperature. Some years ago this expected temperature effect was observed to fail for CO2-H2O, CO2-H2 and CO2-He collisions. Widom and Bauer proposed an explanation for the first of these in terms of a chemical affinity between the CO2 and H2O molecules but their theoretical results were in disagreement with the experimental values available at the time. Recent experimental results have brought measured values more nearly in line with the Widom-Bauer calculations. This paper describes similar calculations for the CO2-H2 system and reports experimental results that indicate the collision efficiency for CO2-He increases normally with temperature. (Author)
Descriptors : (*CARBON DIOXIDE, TRANSPORT PROPERTIES), (*HYDROGEN, TRANSPORT PROPERTIES), (*HELIUM, TRANSPORT PROPERTIES), CHEMICAL BONDS, VIBRATION, TRANSFORMATIONS, PROBABILITY, TEMPERATURE
...
Characterization[ - Google Books Resultby Hellmut G. Karge - 2006
Schematic representation of the fundamental vibrations of carbon dioxide, C02; ... by translational vibrations, slowly modulating the internal vibration, ...
books.google.com/books?isbn=3540643354...
...
Translation to vibration energy transfer in O + NH3 and O + CO2 ...Translation to vibration energy transfer in O + NH3 and O + CO2 collisions. Authors: Bass, James N. Publication: Journal of Chemical Physics, Vol. ...
adsabs.harvard.edu/abs/1974JChPh..60.2913B
...
JSTOR: Vibration-Rotation Energy Exchange in Carbon Dioxide ...Carbon dioxide is de-activated by vibration-translation (v.t.) processes as in (1) COa(0110)+M ->CO2(00 0)+M, AE = 667cm-1. (1) One would expect that ...
links.jstor.org/sici?sici=0080-4630(19760210)348%3A1652%3C57%3AVEEICD%3E2.0.CO%3B2-2
^^
http://www.jstor.org/pss/79116Vibration-Rotation Energy Exchange in Carbon Dioxide-Hydrogen Mixtures. II
C. J. S. M. Simpson, P. D. Gait and J. M. Simmie
Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 348, No. 1652 (Feb. 10, 1976), pp. 57-72 (article consists of 16 pages)
Abstract
Measurements have been made of vibrational relaxation in mixtures of CO2 with 10% 3He, with 10% o-D2 and with 3% HD in the temperature range 1000-360 K by means of a shock tube and a laser schlieren system. These results are compared with earlier measurements using other hydrogen isotopes and isomers. It is clear that there is vibration-rotation exchange between CO2 and n-H2, HD and D2. However, the measured temperature dependence of energy transfer probabilities do not give clear evidence for the importance of long-range interactions in the coupling reaction. It is suggested that the unusually high efficiency of HD in relaxing CO2 is due to the rate of rotational relaxation being a rate limiting process for H2 and D2 but not for HD.
Carbon dioxide is de-activated by vibration-translation (v.t.) processes as in (1)
CO2(0,1^1,0) + M --> CO2(0,1,0) + M, deltaE = 667 cm-1 (15 microns) (1)
One would expect that collision partners having similar intermolecular potentials and the same mass, such as D2 and 4He, would have comparable efficiencies for the (v.t.) process. In fact... not.... ...N2O, HD and 3He.
...
CO2 Vibrations and IR SpectrumVibrations involve movements of the atoms of a molecule which produce no net translation or rotation. These various movements are a result of the ...
www.sens.buffalo.edu/~ajs42/pchem/co2/co2.html - 4k
http://www.sens.buffalo.edu/~ajs42/pchem/co2/co2.html
Energy can be stored in molecules as translational, rotational and vibrational energy. Translation can occur in the x, y or z direction. Rotation can occur around the x, y or z axis, except for linear molecules which only have two axes or rotation. Vibrations involve movements of the atoms of a molecule which produce no net translation or rotation. These various movements are a result of the combination of the normal modes of vibration. For a triatomic molecule these normal modes are symmetric, asymmetric and bending vibrations. In symmetric vibration, the two bonds shorten and lengthen together. In asymmetric vibration, one bond shortens while the other lengthens. In bending vibration, it is the bond angle that oscillates.
http://www.realclimate.org/index.php/archives/2008/04/back-to-the-future/feed/by Rod B.
For all practical purposes the energy from a photon at 15 microns is absorbed in a CO2 molecule’s vibration. This energy is more than twice the kinetic energy of a molecule’s translation at a nominal 300K, and does not affect the temperature, other than from the likely trivial momentum transfer just mentioned. By equipartition quantum probabilities it will strongly want to relax This relaxation is predominately transferring energy to another atmospheric molecule’s translation via collision, at other than very low pressure (density). This does raise the atmosphere’s temperature. It can, though unlikely, transfer to its own translation; however this becomes trivial since the molecule will still quickly relax its new found translation energy again via collision. It can also re-emit a photon instead, the probability of which increases as pressure decreases (among other factors). Conversely, a CO2 can sometimes collide with another molecule, pick up some kinetic energy and immediately relaxing via photon emission, transiting through vibration, and provide a net cooling of the atmosphere
Some of my calculations as a reference (and a check if anyone is so inclined):
The energy of a 15micron photon is 1.325×10^-20 joules; its momentum is 4.4×10^-29 [you’d think by now physicists would have come up with momentum units; I suggest OOMPHS!]
The kinetic energy of a CO2 molecule at 300K is 6.214×10^-21joules (3742 joules for a mol); its momentum is 3.0×10^-23; its velocity (or the average velocity for a mol) is 412.5 m/sec.
One photon’s energy going into one molecule’s translation will raise its temperature from 300K to 630K; the mol’s avg. temp would increase to 300.038K.
The standard relaxation process has a complex formula of probabilities. Of interest is the vibration to translation transfers usually require a large number of collisions before occurring. 10,000 to 100,000 is often quoted, but that is usually at high temperatures (500-1000K) where the molecule is more “comfortable” with its vibration. At atmospheric 200-300K (and normal pressure) it is less : 100-10,000 I would guess (haven’t done the cumbersome math), and more likely to make the transfer. The lower rotation energy takes 5-100 collisions to make a translation transfer and is highly likely — H2O to N2 or O2, e.g. Going the other direction — translation to vibration to emission — I would think (no math again) at low temp and pressure, e.g. stratosphere, somewhere around the 10,000-100,000 collisions range is more the normal and not as likely to occur.
...
In the lower atmosphere there are a lot of CO2 molecules being blasted with thermal radiation from the surface of the earth. They will lose their absorbed vibrational energy to the translational energy of the air molecules through collisions which preserve momentum but transfer energy.
In other words, the surface air will be radiatively heated, just as food is heated in a microwave oven.
Cheers, Alastair.
...
http://www.realclimate.org/index.php/archives/2008/04/back-to-the-future/#comment-85606...
Measurement of the relaxation frequency of the asymmetric ...The vibrational relaxation frequency of carbon dioxide has been determined by .... depends on the temperatures of rotation, vibration and translation. ...
journals.cambridge.org/production/action/cjoGetFulltext?fulltextid=382072
...
Phys. Rev. 134, A407 (1964): Liboff - Vibrations in a Cold ...More precisely, the emergent dispersion relation is sixth order in co2, .... and show that this leads to a translational spectrum in which many states are ...
link.aps.org/doi/10.1103/PhysRev.134.A407
...
A System of Physical Chemistry - Google Books Resultby William Cudmore McCullagh Lewis, William C ... - 1919 - Chemistry, Physical and theoretical
As this is a triatomic molecule we have three atomic vibrations to take account of ... The translational energy plus the rotational energy are in this case, ...
books.google.com/books?id=CpM6AAAAMAAJ...
...
Molecular Heat of COZ. (SO2 has the same molecular heat.)
As this is a triatomic molecule we have three atomic vibrations to
take account of. Two of these, however, may be expected to be the
same, as the oxygen atoms ate presumably linked symmetrically to the
carbon atom. The translational energy plus the rotational energy are
in this case, according to Bjerrum, represented by the term 3RT, i.e.
3/2RT translational and 3/2RT rotational. The wave-length of vibration
of each of the oxygen atoms with respect to the carbon is taken
by Bjerrum to be 5.0microns; the wave-length of vibration of the two oxygen
atoms against each other is taken to be 8.1microns. The formula employed
by Bjerrum is —
Cy(o , T ,) = 3R ~t- 2R<^[_5'o/Aj -r- R<£[_8-1/tJ. [
[quote**Sorry, the math symbols don't translate well**[/quote]
Note that the second term on the right-hand side of this expression
contains the number 2, to allow for the fact that there are two
similar kinds of atomic vibrations present. It may also be pointed
out that if CO2 were a linear molecule, O = C = O, the rotational
energy term would be RT (as in a diatomic gas). The fact that the
value 3/2RT for the rotational energy agrees with experiment (cf. the
following table) means that CO2 is not a linear molecule, its spatial *
constitution being represented approximately by C The constitution
of the CO^ molecule is considered in detail by Bjerrum ( Verh. d.D.
phys. Ges.,16, 737,
The agreement between observed and calculated values is satisfactory.
We have now to see what evidence is available from the absorption
spectrum of CO2 as regards the choice of the wave-lengths employed.
Direct measurement has shown that CO2 possesses bands at 14.7, 4.3,
and 2.7 microns. These are of the same order of magnitude as those used
in the above formula. As a matter of fact, Bjerrum has also used the
three observed values of X and has obtained values for C, which agree....
...
MEASUREMENTS OF VIBRATION-VIBRATION COUPLING IN GAS MIXTURES.The experimental observations are that the component with the faster translation-vibration (T-V) energy exchange rate (NO or CO2 in these mixtures) ...
stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0486480 - 5k -
...
Human Influence on Climate - Science a GoGo's Discussion ForumsIf you're considering kinetic energy only as "translational vibration" ... It is these vibrations that are equated with CO2's absorbed IR at 4-5 microns. ...
www.scienceagogo.com/forum/ubbthreads.php?ubb=showflat&Number=26438&fpart=1 - 102k
uh oh, my "off the top of my head" ramblings have been made citable now. Yikes!!!
...
- lo-’“the translation-vibration energy transfer is. the rate .... Known amounts of carbon dioxide were. added to the gas flow to partially quench ...
ieeexplore.ieee.org/iel5/3/23236/01077326.pdf?isnumber=23236&prod=JNL&arnumber=1077326&arSt=+...
...
is this one of those ...Wacky sites?TEMPERATURE - Access to Energy Newsletter ArchiveQuantum mechanics shows that these vibrations can only take place at discrete ... energy by increasing or decreasing their average translational velocities. ...
www.accesstoenergy.com/view/atearchive/s76a2131.htm - 22k
For a monatomic gas with only only one atom in each unit, the kinetic energy arises only from translational motion - movement of the atom from place to place in three dimensions. For a diatomic molecule, additional motions are possible. These are rotational motion - the two atoms in the molecule spin about their mutual center of mass - and vibrational motion - the two atoms vibrate back and forth by stretching and compressing the chemical bond that holds them together. (Imagine the molecule as a tiny barbell suspended by a string....
Energy transfer to atmospheric molecules occurs primarily by collisions between those molecules and the molecules of warmer bodies and by absorption of energy from electromagnetic radiation.
As you read, you cannot see the tiny diatomic benefactors in the air between your eyes and this page. If they were not there, however, tirelessly bumping into your body and storing and releasing energy by increasing or decreasing their rates of translational and rotational motion, you would be immediately uncomfortable and soon dead.
In these few words, we can communicate only a little about the subject of energy storage in atmospheric gases and the measure of that storage - which is called 'temperature.' This is, however, a very beautiful and exact part of physical science. If you know a student 16 years of age or older to whom you wish to give a lasting gift, get copies of the three books listed above (as sources for Figures 1 to 3) from your library or from interlibrary loan and suggest that he study these books until he understands this subject and all of its associated mathematics.
Notice three things. First, as complicated as this simplified explanation may sound, it is child's play in comparison with understanding the atmosphere of the whole earth - - an ability the global warming industry falsely claims to have acquired. Second, Maxwell insisted that theory agree with experiment if theory were to be considered correct. Global warming calculations have a common characteristic - they do not agree with experiment because they fail to agree with measured atmospheric temperatures. These calculations are fundamentally flawed and cannot be corrected with fudge factors designed to give a politically desirable answer. Third, we are very fortunate to live at a time when the world that surrounds us has been enhanced by science. In previous times, people lived out their entire lives without ever having an opportunity to know about and enjoy the truth about the air around them.
"...and suggest that he study these books until he understands this subject and all of its associated mathematics."
Yes! So they can come back and correct the wacky conclusions that are drawn from your beautiful, factual, and very comprehensible description of the molecular world, and its associated greenhouse/heating mechanisms.
...
Heat capacity ratios for gasesRecall that equipartition theorem says that each translational degree of ... the heat capacity of N2 and CO2 now skipping the contribution from vibration. ...
www.hi.is/~hj/EE2/Verklegt/HeatCapacityRatios/index.html - 8k -
...
Energy Citations Database (ECD) - - Document #5636609... CARBON DIOXIDE-- ATOM-MOLECULE COLLISIONS;CARBON DIOXIDE-- INFRARED SPECTRA;CARBON ... translation-vibration/rotation (T-V/R) energy exchange process. ...
www.osti.gov/energycitations/product.biblio.jsp?osti_id=5636609 - 12k -
...
VIBRATIONS: FROM MOLECULES TO MATERIALS MOLECULAR DANCE HEAT ...File Format: PDF/Adobe Acrobat - View as HTML
Heat conducted through translation; (infrared. radiation) radiated because of molecular .... carbon dioxide and water. in the presence of acid, with C ...
www.cse.iitk.ac.in/~manindra/Website/Vibrations/CALV_01_NSathyamurthy.ppt.pdf -
http://www.cse.iitk.ac.in/~manindra/Website/Vibrations/CALV_01_NSathyamurthy.ppt.pdf
...
Phys. Rev. 133, A750 (1964): Wagner - Resonance Scattering of ...The factor a(cw2) does not alter this picture, as a(co2) is not a strongly .... (b) The translational vibrations of the whole mole- cule; these are the same ...
link.aps.org/doi/10.1103/PhysRev.133.A750
...
[PDF] Fundamentals of SpectroscopyFile Format: PDF/Adobe Acrobat - View as HTML
Example: The two in-plane stretching vibrations of carbon dioxide. ... the normal modes of vibration. These do not include translational or rotational ...
www.polysep.ucla.edu/che212/Notes/polymer%20spectroscopy.pdf - Similar pages
http://www.polysep.ucla.edu/che212/Notes/polymer%20spectroscopy.pdfWOW! Especially if you're into Polymers!
[PDF] Infrared Spectroscopy: TheoryFile Format: PDF/Adobe Acrobat - View as HTML
and 3 are translational. The net number of fundamental vibrations for ... corresponding to the four fundamental vibrations. Carbon dioxide is an example of ...
orgchem.colorado.edu/hndbksupport/irtutor/IRtheory.pdf
http://orgchem.colorado.edu/hndbksupport/irtutor/IRtheory.pdf[PDF] Could this New Technology Prolong Life on Earth? Radiolytic ...File Format: PDF/Adobe Acrobat - View as HTML
can have atoms with translational (linear) as well as rotational ..... UV or laser light to the irradiation chamber, apply ultrasonic vibration to the gas ...
www.netl.doe.gov/publications/proceedings/01/carbon_seq/p11.pdf The solutions offered to solve or mitigate the effect of global warming are many,
including:
1. Conduct more studies of greenhouse effect on global environment
2. Devise more workable global plan to limit the quantity of CO2 released to the atmosphere
3. Develop new technologically driven alternatives to CO2 producing energy sources
4. Curtail cutting down forested areas around the globe
5. Conduct CO2 sequestration of CO2 in large industrial plants
6. Mitigate the greenhouse effect by modification of life forms and plant growth on the earth
and ocean
7. Develop technologies that can economically or near economically convert CO2 to an
intermediate or final useable product
Of the seven general means listed for minimizing the greenhouse effect on the earth, only
number 2 has the capability to have an immediate impact on the global environment.
...
[DOC] Vibrational spectroscopyFile Format: Microsoft Word - View as HTML
Consider now carbon dioxide, O=C=O. The 3N-5 rule for vibrational degrees of freedom predicts 4 ... molecule, total, translation, rotation, vibration ...
garfield.chem.elte.hu/Turanyi/oktatas/gyogyszeresz/optical%20spectroscopy%20(lecture%20notes)/L09Vib.doc
...
Science Magazinecontrol the translational energy precisely) with ... vibration and translation enhance the reac- .... Carbon dioxide is taken up more by the ...
www.scienceonline.org/cgi/reprint/sci;316/5832/1707.pdf
Equipartition of EnergyTranslational - movement in the x,y,z position of the molecule-always 3 and only 3 of ... Vibration has both a potential and a kinetic energy component. ...
webpages.marshall.edu/~larson/c357/Equi.htm - 4k -
...
"CO2 translational vibrations" --> end
??
Simple Mathematical Expressions for Spectral Extinction and Scattering Properties of Small Size-parameter Particles, Including Examples for Soot and TiO2
Journal of Quantum Spectroscopic Radiation Transfer ; Year: 1996 ;Volume: 55 ;Issue: 3 ; p. 391-411
...a little light reading?
