Down-shift model

Besides all these quant-related constraints there are numerous others such as down times for production equipment when maintenance or rebuilding activities have to be carried out or fixed production orders. Finally, there are constraints such as varying shift models, and so forth. 

In order to compare ab initio SOS/CIS with TDHF calculations we have evaluated the SFG response of two model chiral compounds, R-(- -)-propylene oxide and R-mono-fluoro-oxirane. The computed excited state energies have all been down-shifted by 2.675 eV for R-(- -[-propylene oxide (and 2.27 eV for R-mono-fluoro-oxirane) [59]. Figure 5 shows that both methods calculate very similar magnitudes and dispersions of the SFG pseudoscalar. 

Fig. 6.8. The dependence of rj2 on x) by the Ivanov model (I) and friction model (F) in comparison with predictions of the extended. /-diffusion (ED) and Langevin (L) models for linear molecules. The line (H) corresponds to the Hubbard inverse proportionality between xgj and xj at very high densities. Experimental data from [81] are in rectangles around line G with the length of their vertical and horizontal sides being equal, correspondingly, to the experimental errors in x el and rj measurements. Experimental data from [270] (J) are shown both in original position and shifted down by a factor of four (broken line).

Consideration of the feasibility of these shifts as concerted processes, i.e. via cyclic transition states, requires as usual a consideration of the symmetry of the orbitals involved. A model related to the transition state can be constructed by the device of assuming that the C—H a bond that is migrating can be broken down into a hydrogen Is orbital and a carbon 2p orbital. For the case where x = 1 in (36), the T.S. can then be considered as being made up from a pentadienyl radical (38), with a hydrogen atom (one electron in a Is orbital) migrating between the terminal carbon atoms of its Site system (i.e. a 6e system overall is involved) ... 

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