Attractive or repulsive interactions between the adsorbate molecules make the desorption parameters Edes and V dependent on coverage [17], [Pg.39]

Problem 11-5. If there is no significant attractive or repulsive interaction between two radicals, the probability of first encounter at r=d from the initial distance at r=ro is expressed as [Pg.162]

Electrostatic coulombic interactions Attractive or repulsive interactions [Pg.101]

In the previous sections, we saw that, in most cases, a nonbonded attractive or repulsive interaction is enforced by both four electron destabilization and two electron stabilization. Hence, in order to simplify subsequent discussions, we shall adopt the OEMO model with neglect of overlap. Consequently, in the remainder of this work [Pg.40]

Let us first consider the situation when macromolecules do not exhibit any attractive or repulsive interaction with the porous column packing surface except for the effects caused by the imperviousness of the pore walls. This corresponds to AH=0 in Equation (17) and the sample retention volume is controlled exclusively by the entropy of process. The fictitious retention volume of eluent molecules corresponds to total volume of liquid within column, becanse the small molecules [Pg.249]

Two - particle energy correction correction to electron - electron correlation energy due to the phonon field. This non-adiabatic term represents full attractive contribution, and can be compared to the reduced form of Frohlich effective Hamiltonian which maximizes attractive contribution of electron - electron interaction and that can be either attractive or repulsive (interaction term of the BCS theory). For superconducting state transition at the non-adiabatic conditions, the two-particle correction is unimportant - see [2], [Pg.91]

The assumptions made to derive the Langmuir isotherm (Eq. 2.7) are well known Energetic equivalence of all adsorption sites, and no lateral (attractive or repulsive) interactions between the adsorbate molecules on the surface. This is equivalent to a constant, coverage independent, heat (-AH) of adsorption. [Pg.20]

With the aid of (B1.25.4), it is possible to detennine the activation energy of desorption (usually equal to the adsorption energy) and the preexponential factor of desorption [21, 24]. Attractive or repulsive interactions between the adsorbate molecules make the desorption parameters and v dependent on coverage [22]- hr the case of TPRS one obtains infonnation on surface reactions if the latter is rate detennming for the desorption. [Pg.1863]

We have already made use of the so-called mean-field approximation by assuming that (1) all adsorbed species are distributed randomly over the surface and (2) there is no interaction betv een the adsorbed species. This is an approximation that is seldom fulfilled. Usually there vill be either an attractive or repulsive interaction [Pg.52]

In the simplest case, all equilibrium positions of sorbate molecules in the solid are equivalent, and the state of a sorbed molecule is independent of the presence of other sorbate molecules in the solid. The sorbent is thus considered to be energetically homogeneous with respect to its interaction with the sorbate, and it is assumed that there is no attractive or repulsive interaction between the sorbate molecules. [Pg.285]

Let us consider the various possible types of biopolymer-surfactant interactions. We first note that, because of the amphiphilic nature of both biopolymers and surfactants, it can be envisaged that the mechanistic interpretation could be based on attractive or repulsive interactions acting between the original biopolymer and surfactant molecules/particles or between biopolymer particles modified by the surfactants. For example, attractive interactions could arise from [Pg.176]

We note that the boundary conditions chosen in Eqs. (57) to (58) model the particular situation of electrostatic attraction in competition with a short-range (steric) repulsion of nonelectrostatic origin. Possible variations of these boundary conditions include surfaces with a constant surface charge (discussed later) and surfaces with a nonelectrostatic short-range attractive (or repulsive) interaction with the polymer [83, 127]. Far from the surface (jc -> oo), both f and f reach their bulk values and their derivatives vanish f x oo = 0 and f x oo — 6. [Pg.306]

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