Precessors

Sulphide and sulphoxide complexes have been extensively studied since cis-RuC12(DMSO)4 (DMSO, dimethyl sulphoxide, (Me)2SO) was found to have anti-tumour properties and to be a precessor for radiosensitizing agents. Such complexes can act as catalysts for the oxidation of sulphides with molecular oxygen. 

Appendix 1. Calculation of Fourier Amplitudes b -i for Librators Appendix 2. Transformation of Integral for Spectral Function of Precessors Appendix 3. Optical Constants of Liquid Water... 

X and X, X, X Statistical integral and its part, corresponding to contributions of librators, precessors, rotators... 

The proportions of the librators, precessors, and rotators are defined as the normalized weights ... 

It is important to compare the parts of the absorption band, generated by the librators, precessors, and rotators. In Fig. 22c and 22d we show evolution of these partial frequency dependencies, when the form factor/decreases from 0.8 to 0.65. These and other parameters (it = 6, (I 23°) are chosen to be typical for water. In the first case, Fig. 22c, the contribution of the precessors to the total absorption is negligible in the second case, Fig. 22d, it is less than 5%. Therefore, for the set of parameters typical for water, the absorption spectrum is actually determined by the librators and the rotators. 

The estimated positions of maximum absorption (see vertical lines in Figs. 22c and 22d are close to the peak frequencies found from Eqs. (171)-(173) and (179). The peak frequency (190a) is inversely proportional to p it increases with the decrease in the form factor/or with the increase of the well depth u, see, respectively, Fig. 23a and 23b. The proportions of the librators, precessors, and rotators are calculated from Eq. (184) and presented in Fig. 23c and 23d by solid, dash-dotted, and dashed curves, respectively. Figure 23c shows relevant functions of the reduced well depth u and Fig. 23d—of the form factor/. 

In an important case of a deep well and/close to 1, the main fraction is the librators. The proportion of the precessors is very small and their contribution to the FIR spectra is negligible as we have already demonstrated in Figs. 22c and 22d. The proportion of the rotators in this case is only a few percent. However, the rotators substantially affect the FIR and low-frequency spectra of water (it will be demonstrated in the Section V.D). 

Finally, neglecting the term in Eq. (184) pertinent to precessors, we can estimate the proportion r of the rotators as... 

Figure 27. Evolution of the phase regions occupied by the librators (XC) and by the precessors (HP) with the increase of the form factor / from 0.65 (a) to 0.85 (b). The angular width of the hat-curved potential well, p, is n/9, and the reduced well depth, u, is 5.9.

The phase regions occupied by the librators and precessors are depicted in Fig. 27 in coordinates h, l2 for the parameters u = 5.9, p = %/9. We take two values of the form factor/ 0.65 in (a) and 0.85 in (b). When/increases, the / and 2P areas extend to the larger h and l values. The values of Vmin are shown as functions of l in Fig. 21c. In this example (and in the calculations described in Section V.C) the potential well depth U0 is much greater than kBT, that is, u> 1. We see in Fig. 27 that for the J and 2P areas the boundary values for h are still greater than it. This property is used to simplify analytical expressions for the spectral functions. 

APPENDIX 2. TRANSFORMATION OF INTEGRAL FOR SPECTRAL FUNCTION OF PRECESSORS... 

Substituting all variables into integral (A2) and taking into account Eq. (197d), we finally derive Eqs. (174)-(178) for the spectral function of the precessors. 

We neglect, just as in Section V, the contribution to spectra due to the precessors, since this contribution is very small. 

All the dipoles could be distributed over three groups comprising librators, precessors, and rotators. Our calculations are made in the planar libration— regular precession approximation. For the set of parameters relevant to water (with ( 1 and u > 1) the contribution of the precessors to the spectral... 

The regions C and V, to which the spectral functions L(z) and L(z) correspond, are occupied by the particles localized in the well. Any -particle penetrates into the flat part of the well. We may conditionally call it libratorThe P-particle, conditionally called precessor, move only in the parabolic part of the well and has energy h close to that, for which the effective potential V(9) undergoes its minimum, in which... 

In our calculations, made in Sections II through V, the neglect of item (i) allows to avoid worsening of the theoretical absorption spectrum. One may suppose that the trajectories, ascribed to these precessors, cannot simulate real ... 

Hence, for the transition from the full expression (210) to the simplified (8)-(10) (a) in Eq. (175), containing the normalizing coefficient C, the contributions of precessors and rotators were disregarded. Moreover, we removed a misprint committed in GT2 and inserted additionally in the formula for D the factor d equal to 0.7. One may interpret this factor as that, which accounts for influence of surrounding molecules on the spectral function (8). 

We have also shown that some originally proposed (e.g., in GT2) properties of the hat potential turn out to be excessively abstract, so that we disregarded them. We mean here (i) absence of free rotors, performing circular motion, since in the water/ice structure there is no place for such a motion, and (ii) nonexistence of precessors, since, as it appears, the libration of dipoles in a diametric cross section of the hat-like potential well dominates. On the other hand, the well s curvature is important for modeling the spectra, since, unlike the well depth, this curvature strongly depends on temperature and fluid phase state. 

Before the advent of UF, juice precessors hydrolyzed cloud-stabilizing polysaccharides such as pectin and starch with pectinase, coagulated with gelatin, and then clarified the cloudy cider with a diatomaceous earth filter. The materials collected on the filter provided an ideal substrate on which to grow and multiply bacteria. This resulted in high microbial counts in the juice, but high temperature pasteurization is not desirable because of its effect on flavor. 

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