Gouy-layer

Gouy layer Gouy method Government policies... 

The region of the gradual potential drop from the Helmholtz layer into the bulk of the solution is called the Gouy or diffuse layer (29,30). The Gouy layer has similar characteristics to the ion atmosphere from electrolyte theory. This layer has an almost exponential decay of potential with increasing distance. The thickness of the diffuse layer may be approximated by the Debye length of the electrolyte. 

The outer layer (beyond the compact layer), referred to as the diffuse layer (or Gouy layer), is a three-dimensional region of scattered ions, which extends from the OHP into the bulk solution. Such an ionic distribution reflects the counterbalance between ordering forces of the electrical field and the disorder caused by a random thermal motion. Based on the equilibrium between these two opposing effects, the concentration of ionic species at a given distance from the surface, C(x), decays exponentially with the ratio between the electro static energy (zF) and the thermal energy (R 7). in accordance with the Boltzmann equation ... 

Helmholtz and Gouy layers, capacitance as a function of, 36 HF generation hazards (Peters and Miethschen), 524... 

The diffuse layer of excess electrons and holes in solids is called the space charge layer and the diffuse layer of excess hydrated ions in aqueous solution is simply called the diffuse layer and occasionally called the Gouy layer [Gouy, 1917]. The middle layer of adsorbed water moleciiles, between the diffuse layer on the aqueous solution side and the space charge layer on the soUd side, is called the compact or the inner layer. This compact or inner layer is also called the Helmholtz layer [Helmholtz, 1879] or the Stem layer [Stem, 1924] the plane of the closest approach of hydrated ions to the solid surface is called the outer Helmholtz plane (OHP) [Graham, 1947]. 

The potential drop in the Gouy layer in the solution ( LH) — —oo) is usually denoted in the electrochemical literature by , the psi-prime potential. The second term in square brackets in Eq. (12) represents the potential drop in the Helmholtz layer it will be denoted by . Finally, the last term in square brackets is the potential drop in the space-charge region in the semiconductor. 

Figure 2.6 Stem and Gouy layers above a mineral surface in an aqueous solution. Circles in the Gouy layer represent water molecules surrounding the ions.

Adsorption in Reactions 2.47-2.52 also involves ion exchange (Eby, 2004), 345. During the formation of inner-sphere complexes, adsorbing arsenic commonly replaces hydroxides or other chemical species on the surface of the adsorbent. Complexes in Stern outer-sphere and Gouy layers are also susceptible to ion exchange, especially because they are weakly adsorbed (Krauskopf and Bird, 1995), 150. 

Double layer Two layers of ions associated with a charged particle in an aqueous solution. The Stem layer is attached onto the surface of the particle. The diffuse Gouy layer surrounds particle and its Stem layer. 

Gouy layer A diffuse layer of ions surrounding a charged particle in an aqueous solution. The Gouy layer ions do not come into contact with the particle surface, but are separated from it by the Stern layer. In the Gouy layer, the imbalance between cations and anions exponentially decreases with distance away from the solid surface. The Gouy and Stern layers comprise the double layer. 

Another layer of counter-ions will also form a diffuse layer surrounding the Stem layer, which is called the Gouy layer. The Gouy and Stem layers as well as the Helmholtz plane are shown in Figure 1. 

FIGURE 9,14 Schematic representation of molecular arrangement dose to a solid surface showing the inner (IHP) and outer (OHP) Helmholtz planes, the stem layer, difAise double layer, also called the Gouy layer, and the slip plane where the zeta potential is measured. Also shown is the potential for various distances from the surface. 

All of the charges in the Stem layer move with the colloid thus, this layer is a fixed layer. In the Gouy layer, part of the layer may move with the colloid particle by shearing at a shear plane. This layer may shear off beyond the boundary of the fixed Stem layer measured from the surface of the colloid. Thus, some of the charges in the layer move with the particle, while others do not. This plane is indicated in Figure 12.3. 

Electric double layer—The layers surrounding a colloid body composed of the Stem and Gouy layers. 

Gouy layer—A diffuse layer of colons to the primary charges surrounding the Stem layer. 

Figure 6. Electrostatics at a semiconductor-electrolyte interface. A very simplified equivalent circuit for the interface at equilibrium is shown at the bottom. The Gouy layer is neglected in the latter case (see text).

---