Carbon dioxide infrared spectra

Figure 11.46. (a) Recording of the 21,2 <— 17,1 vibration-rotation transition of the HD+ ion, obtained by Doppler tuning the ion beam into resonance with a carbon dioxide infrared laser beam [88], (b) A radiofrequency/infrared double resonance spectrum obtained by pumping the v3 line shown in the infrared spectrum (see text for the assignment). 

After water vapor and C02, methane (CH4) is the third most important greenhouse gas. Each additional molecule of CH4 added to the atmosphere absorbs about 20 times as much long-wave infrared radiation as does a molecule of carbon dioxide. This occurs in part because some of the absorption spectrum of methane lies in windows in the carbon dioxide absorption spectrum (see Fig. 4-42) therefore, methane absorbs wavelengths that are not already being highly attenuated by carbon dioxide. Currently, the global concentration of methane in the atmosphere is approximately 1.7 ppm and is increasing at an annual rate of approximately 0.01 ppm per year (Table 4-14). The seasonal fluctuations shown in Fig. 4-44 may correspond to seasonal... 

The supercritical CO2 absorption bands change in intensity as a function of density but the band shape does not change - at least not at the 8 cm spectral resolution typically used for this application. As a result, it is a simple matter to subtract the supercritical carbon dioxide absorption spectrum from an FT-IR data file collected during an SFC/FT-IR experiment. The subtraction factor is adjusted to exactly compensate for the Fermi resonance absorption. The resulting spectrum will then contain only absorption bands due to other components, if any, entrained in the supercritical fluid. The regions from 3800-3500 cm and from 2500-2200 cm appear as gaps in the spectrum because the supercritical carbon dioxide absorbs all the available infrared radiation in these regions. 

A particular vibration will give an absorption peak in the IR spectrum only if the dipole moment of the molecule changes dunng the vibration Which vibration of carbon dioxide the sym metric stretch or the antisymmetric stretch is infrared active 2... 

Figure 19. Infrared spectrum of iron oxide. Water and carbon dioxide bands...

Chemoluminiscent radiation as shown by spectroscopic analysis of a flame is so small that in calculations of thermal losses it may be neglected we will be interested in thermal radiation, whose intensity is determined by the composition and temperature of the gas. Transparent, colorless gases radiate in the infrared part of the spectrum. Significant and well-studied radiation is given off by water vapors and carbon dioxide. 

Oxodecanoic acid. Dissolve 4.0 g of 3-carboxy-3,4-dibromodecanoic acid in 60 ml of 2m sodium hydroxide solution and heat the solution at 80-90 °C for 2 hours. Cool to room temperature and acidify with dilute sulphuric acid carbon dioxide is evolved and a white precipitate is formed. Filter the precipitated keto acid from the cold solution and recrystallise from light petroleum (b.p. 40-60 °C). 4-Oxodecanoic acid, m.p. 68-69 °C, is obtained the yield is 1.6 g (80%). The infrared spectrum shows absorptions at 3400-2400 cm-1 (OH stretch of COzH) and 1700 cm-1 (0=0). 

We remember that there were very few far-infrared laser lines available at the time, all of them discharge laser lines. Unfortunately, although there is a spectacular series of coincidences between the lines of the water discharge laser and the spectrum of the OH radical, the same is not true for CH. The only good coincidence is the 118.6 pm line used by Evenson, Radford and Moran [48]. Progress on the far-infrared spectrum of CH had therefore to await the development of new far-infrared laser lines, optically pumped by an infrared carbon dioxide laser. With these laser lines, two further studies of CH in the ground 2 n state were made in the Boulder laboratories, by Hougen,... 

Figure 9.21. FIRLMR spectrum of CH [53]. The spectra were recorded using a laser wavelength of 124.4 pm. The lasing medium was CH2DOH, pumped by the 10P(34) infrared line of carbon dioxide. The rotational transition involved is N = 3 2, J = 5/2 - 5/2, — <—h...

The infrared spectrum of CO2 radical ion (prepared by depositing sodium atoms on solid carbon dioxide) has been obtained and has bands... 

Fourier transform/infrared spectrometry (FT/IR) detects and identifies CWAs by measuring the infrared spectrum of the air sample noninvasively and instantly (Mukhopadhyay 2004). Considering the interference of water and carbon dioxide, characteristic absorbance peaks in the low-wave number region are used as the specific marker. Portable FT-IR equipment is commercially available. IGA-1700 (Otsuka Electronics, Japan) and DX-4000 (Temet, Finland) showed... 

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