Ozonizer molecular orbitals

Oxidation rate constant k, for gas-phase second order rate constants, kon for reaction with OH radical, k os with NOj radical and koj with O3 or as indicated, data at other temperatures see reference photooxidation half-life of 0.24-2.4 h in air for the gas-phase reaction with OH radical, based on the rate of disappearance of hydrocarbon due to reaction with OH radical (Darnall et al. 1976) k < 0.8 M s for the reaction with ozone in water at pH 2 and 20-23°C (Hoignd Bader 1983) koH = (13.6 1.3) X cm molecule s at 298 K (Wallington et al. 1988a Atkinson 1989) kojj = (14.4 1.5) X 10 2 cm molecule s at 298 2 K (relative rate method, Nelson et al. 1990) koe(calc) = 11.67 X 10 cm molecule s (molecular orbital calculations, Klamt 1996)... 

Localized Molecular Orbitals ILMOl. 227 MOMEC force held. 40 Ozone, 115, 287 ... 

Prepare a molecular orbital energy level diagram for the ozone molecule, O3, for each of the following conditions ... 

The azide radical is linear, as is its anion. Ozone, sulfur dioxide, and N02 are bent in the neutral form and in the anion. The neutrals of C02, CS2, COS, and N20 are linear and the anions bent, as predicted by simple molecular orbital theory. The electron affinities of these species are uncertain [90-102], In Figure 9.17 the ECD data for these compounds are shown. The diversity in the temperature dependence of the isoelectronic molecules is remarkable. The ECD response of C02 is unexplained. The temperature dependence for CS2 is typical of nondissociative electron attachment to two states. The low-temperature dependence of COS is unusual, but can be attributed to attachment to two states with a low A. Dissociative electron attachment and molecular ion formation are observed in the ECD data for N20. Consequently, only an upper limit to the electron affinity may be obtained [90-93],... 

Despite the huge increase in computational effort, this direct symmetry-adapted LCAO method was used to study ozone [22], tetrahedral Ni4 [23], and D5h-symmetric ferrocene (Fe(C5H5)2) [24] using molecular orbital (MO) contraction coefficients in the linear-combination-of-Gaussian-type orbital (LCGTO) computer code of [25]. Obviously, symmetry-adapted calculations are important enough to pay an order-TV computational price. The reasons are first, and foremost, that the calculations converge, and second that the wavefunction and one-electron orbitals can be used to address experiment, which typically must first determine the symmetry of the molecule. 

Figure 11.21. Frontier orbital interactions of ozone and ethene. [Reprinted with permission from Fleming, i. Frontier Molecular Orbitals and Organic Chemical Reactions, Wiley, London, 1976, pp. 93. Copyright 1976 by John Wiley and Sons, Inc.]...

The ozone molecule is angular and therefore has the symmetry C2 . Using the valence shell orbitals on each of the three oxygen atoms, construct molecular orbitals of the proper symmetry let 0(2) and 0(3) be equivalent. The orbitals, Xi to Xi2> are labeled in the order (2s)y (2pjy ... 

Calculate and display the molecular orbitals of the ozone molecule, O3. Which orbitals show ir interactions Compare your results with your answer to Problem 5.19. 

What are the Lewis structures for the two allotropic forms of oxygen How can the paramagnetism of O2 be explained using the molecular orbital model What are the molecular structure and the bond angles in ozone ... 

Molecular orbital correlation diagram for ( 4s -I- cycloaddition of ozone and ethene. (Adapted from reference 122.)... 

Because we start with three atomic orbitals, we can construct three molecular orbitals. The general procedure for determining the values of the coefficients Ca, Cb, and Cq for these three molecular orbitals is mathematically involved in the present case, however, we can use what we know about the symmetry of the problem and the general behavior of electron wavefunctions to obtain a very good qualitative picture of the molecular orbitals. First, the ozone molecule is symmetric, with a mirror plane bisecting the O—O—0 bond angle. Reflection of the molecular orbital through this... 

Figure 4.22 Surface boundary plots of the three tt molecular orbitals in ozone discussed in text. Left to right i/ i, ifc, and i/f3. i/ i is an occupied bonding orbital, i/ 2 is an occupied nonbonding orbital, and the antibonding orbital is unoccupied. Blue and red denote + and - regions of the orbitals, respectively.

This simple MO pictnre for ozone can also be employed to describe the bonding in other bent triatomic molecnles of second-row elements, such as NO2. Example 4.7 applies molecular orbital theory to CO2, a linear second-row triatomic molecule. 

Bonding in many polyatomic molecules, such as ozone or benzene, can often be best described in toms of delocalized molecular orbitals. 

Using ozone as a model, describe the tt bonding in NO2 using a molecular orbital scheme. 

Figure 6.3. Representations of the molecular orbitals of ozone (Oj). The representations were created using the MOViewer in WebMO version 6.0.002p.

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