Ozone absorption spectrum

The importance of this high concentration of ozone in the stratosphere resides in its effects on radiation and associated feedbacks. Figure 12.2 shows the ozone absorption spectrum, which was discussed in detail... 

The absorption cross section on the ordinate of the ozone absorption spectrum at the beginning of this chapter is defined by the relation... 

Thus ozone absorption spectrum has been studied in the UV (200-500 nm) and visible (450-700 nm) regions at ambient and low temperatures down to 218 K. 

Louis Soret was a professor of physics at the University of Geneva He studied the laws of electrolysis, defined the conditions for the production of ozone and determined its density and chemical constitution devised ingenious optical instruments and was the first scientist to make actinometnc measurements on the summit of Mont Blanc (67). In 1878 he recognized the presence of a new earth X in erbia and characterized it by its absorption spectrum, but later accepted the name holmia which Cleve gave it (67). He died in Geneva in 1890 at the age of sixty -three... 

One of the first examples of the modem application of remote sensing of the composition of the atmosphere was the assertion by Hartley in 1880 that the UV absorption in the solar absorption spectrum was attributable to ozone. In this manner the earth s stratospheric ozone layer was discovered. Since this pioneering work and especially in die past 30 years, there has been rapid progress in the development of atmospheric remote sensing techniques. 

Fig. 4. Absorption spectrum of ozone in the Hartley band region. This figure based on ref. (48) and used with the permission of the Journal of the Optical Society of America.

The existence of the fugitive, paramagnetic trioxide NO3 is also implicated in the N2O5-catalyzed decomposition of ozone, and its concentration is sufficiently high for its absorption spectrum to be recorded. It has not been isolated as a pure compound, but probably has a symmetrical planar structure like that of NOJ. 

The details of the ozone absorption spectrum26-26 are not nearly as well understood as those of the oxygen spectrum. Taube27 has summarized the energetics of the decomposition of ozone and a somewhat more extensive tabulation is presented in Table IV. 

In particular the autoxidation of benzaldehyde was investigated. Its choice as the initial subject for study was unfortunate, as the use of an impure sample of perbenzoic acid for determination of its absorption spectrum, not previously recorded, led to erroneous conclusions. These were later rectified after taking new measurements on a pure crystalline sample of the peracid (12). For the present study the two main bands at 1728 to 1730 and at 1270 cm.- are to be borne in mind. These bands made possible a demonstration of the acceleration of the autoxidation due to ozone and the influence of such acceleration in ozonide formation. Three spectral series (Figures 1, 2, and 3), obtained in collaboration with E. Dallwigk, are discussed below. 

It is convenient to discuss three regions of the absorption spectrum, separately the Hartley band from 2000 to 3000 A., the Huggins band from 3000 to 3500 A., and the Chappuis band from 4000 to 7500 A. The results of the ozone absorption coefficients measurements are displayed in Figures 2, 3, and 4, respectively. The absorption coefficients measured by the authors are tabulated in Table I. 

Once we have verified that the polyynes in dilute solution are stable to air oxidation, we studied the effect of a more powerful oxidizing agent ozone. Figure 18.12(A) (bottom curve) shows the electronic absorption spectrum of the polyynes solution in DHNP. I he addition of O3 to this solution causes an increase in the intensity of the bands at 220 and 232 nm (Figure 18.12A, top curve) this increase in the absorption intensity is due to ozone dissolved in DHNP which has an absorption maximum just in this wavelength range. However, a reduction in intensity can be observed in Figure 18.12(A) for the other bands at 257, 245, 282, 303, and 322 nm as a consequence of the ozone treatment. This fact can be better appreciated by the spectrum difference... 

Carbon dioxide is a linear molecule which has a relatively simple absorption spectrum. One of the strongest bands is the v2 fundamental at 15 pm, which contributes significantly to the energy budget of the atmosphere. The v3 band at 4.3 pm is also strong and rivals heating by ozone in the middle mesosphere. Additional weak bands centered in the 12-18 pm, 10 pm, and 7.6 pm regions must be considered in the CO2 climate problem, as discussed by Kiehl and Dickinson (1987). 

Fig. 2-8. Absorption spectrum of ozone in the wavelength region 115-350 nm, with cross sections given in units of cm2/molecule. Data used are from Inn and Tanaka (1953), Tanaka el al. (1953), and Griggs (1968).

In the N205-catalyzed decomposition of ozone, the steady-state concentration of N03 can be high enough to allow its absorption spectrum to be recorded. 

HNO3 (430 transitions in the region 1690—1727cm ). The i.r. spectrum of was investigated over the sample temperature range 800—1050 Eight ozone absorption lines around 1068.7 cm were resolved using a Pb salt... 

Ozone is formed in the stratosphere by the short-wavelength (< 240-nm) homolysis of molecular oxygen (O2) to two oxygen atoms (O), followed by the subsequent collision of an oxygen atom with an oxygen molecule to produce O3. The absorption spectrum of ozone (X ax = 255 nm) is such that virtually all the potentially damaging ultraviolet wavelengths between 200 and 300 nm are screened out before they reach... 

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