Attachment coefficient average, calculations

Theoretical calculations of unattached fractions of radon progeny require prediction of an attachment coefficient. Average attachment coefficients for aerosols of various count median diameters, CMD, and geometric standard deviations, ag, are calculated using four different theories. These theories are ... 

From Figure 1 it can be seen that Fuchs theory and equation (5) predict similar attachment coefficients. Equation (5) is therefore used in calculating average attachment coefficients. 

The average attachment coefficient 3 can be calculated for the diffusion and the kinetic theory from the equation ... 

The kinetic-diffusion approximation predicts an attachment coefficient similar to the hybrid theory for all CMDs and for both Og m 2 and 3 (Figs. 3 and 4). The advantage of this theory is that the average attachment coefficient can be calculated from an analytical solution numerical techniques are not required. 

The fluid model is a description of the RF discharge in terms of averaged quantities [268, 269]. Balance equations for particle, momentum, and/or energy density are solved consistently with the Poisson equation for the electric field. Fluxes described by drift and diffusion terms may replace the momentum balance. In most cases, for the electrons both the particle density and the energy are incorporated, whereas for the ions only the densities are calculated. If the balance equation for the averaged electron energy is incorporated, the electron transport coefficients and the ionization, attachment, and excitation rates can be handled as functions of the electron temperature instead of the local electric field. 

Figure 1 ROHF and UHF valence MOs of the methyl radical. The numbers under each MO denote the ratio of the AO coefficients on carbon and on the hydrogens (from an STO-3G calculation). Note how this ratio differs in the paired UHF MOs, illustrating the tendency of the P electrons to avoid the carbon atom where the a electron in the SOMO is localized. Note also that the ratio of AO coefficients in the ROHF MOs is about the average of those in each of the corresponding pairs for UHF MOs. The numbers at the bottom denote Mulliken spin densities p on carbon and on each hydrogen attached to it.

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