Electrostatic force comparison with other forces

More recently, Deryaguin has emphasized the fact that the force of attraction between the plates of a condenser is independent of their separation, in contrast to the distance-force relationships of other types of attraction. Thus, while at small distances electrostatic forces may be negligible by comparisons with others, as the distances become greater, the relative significance will change and the electrostatic forces become significant. 

The other colloidal forces can be compared by taking ratios of characteristic energies, that is, A for the dispersion force, exlr a for electrostatic repulsion, and a5 (l / 2 - x)kT/vs for polymer stabilization. A comparison with Brownian motion (Russel, 1980) leads to the following dimensionless groups ... 

Comparison of the Av values of diastereomeric complexes with 2-butanols, 2-pentanols, and 2-butylamines indicates that relative extent of electrostatic and dispersive forces depends upon the namre, the bulkyness, and the configuration of M. The A(Ar> ) = ((Ar )ijonjo — (Ai )i,etero) = +13 cm difference between the red shifts of the homochiral and the heterochiral complexes with 2-butanols finds a close analogy with LIF red-shift difference of the corresponding adducts with F/ = (/ )-(+)-2-naphthyl-l-ethanol (A(Ai ) = ((Aji)homo (AF)hetero)= +H cm Table 1). However, while LIF results from the diastereomeric [F/j M] (M = 2-pentanol) complexes are qualitatively similar to those with the other secondary... 

Table III shoves the comparison of the calculated potential energy of neopentane on NaX zeolite with the experimental value of the heat of adsorption (O. M. Dzhigit, A. V. Kiselev, L. G. Ryabukhina, Zh. Fix. Khim. 1970, 44, 1790). Two models, 1 and II (Figure 3), of the distribution of the force centers in zeolite NaX and two orientations, (1) and (2), of the neopentane molecule at site Sn (Figure 4) were used. The calculations show that for approximate evaluation of potential energy, it is only necessary to take into consideration about 50 nearest charged oxygen atoms and 4 cations. In model II, the influence of other cations (which are situated in sites Sn of the supercage) were taken into consideration. The other cations, which are distributed more randomly, do not influence seriously the electrostatic fleld in the space occupied by the neopentane molecule near one of the Sn sites (calculations by L. G. Ryabukhina and A. A. Lopatkin).

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