Ion-induced dipole attraction

Potential functions used82 were an exp-6 function with two free repulsive parameters and a modified exp-6 with three repulsive parameters. The modification was introduced as a screened ion-induced dipole attraction, which softens the repulsion at small r. The fitted potentials are shown in Fig- 10. The dashed curves in Fig. 9 show the fits obtained with the simple exponential repulsion and the solid curves with the modified repulsion. 

Favourable thermochemistry for a particular gas-phase reaction does not guarantee that it will be kinetically viable. Although many gas-phase ion-molecule reactions are fast owing to the ion-dipole and ion-induced dipole attractive electrostatic potential, there can be significant barriers to certain reactions. Hence experimental kinetic data are important, especially for the modelling of atmospheric and interstellar processes. Those interested in the kinetics of gas-phase ion-molecule reactions involving phosphorus species are directed to a number of databases. ... 

An ion-induced dipole force results when an ion in close proximity to a non-polar molecule distorts the electron density of the non-polar molecule. The molecule then becomes momentarily polarized, and the two species are attracted to each other. This force is active during every moment of your life, in the bonding between non-polar O2 molecules and the Fe " ion in hemoglobin. Ion-induced dipole forces, therefore, are part of the process that transports vital oxygen throughout your body. 

Early attempts to describe bimolecular gas phase ion-molecule reactions were based on the classical collision dynamics of a point charge and a structureless polarizable neutral molecule. The collision process is dominated by the long range attractive ion-induced dipole potential V(r) given by (16),... 

Was this your answer If you haven t yet formulated an answer, why not back up and reread the question You ve got only four choices ion-dipole, dipole-dipole, dipole-induced dipole, and induced dipole-induced dipole. The answer is induced dipole-induced dipole attractions, because the interaction is between two nonpolar entities—the grime and the nonpolar tail of a soap or detergent molecule. 

Which is stronger, the ion—dipole attraction or the induced dipole—induced dipole attraction ... 

Sf/scwMb t)e calculated from Eq. (2.109) if v scw known. Waters that are not coordinated solvationally with the ion (NSCW) have as attractive force only an ion-induced dipole component (AW ,). Thus, the force constant k/ cw can be worked out by using Eqs. (2.111)-(2.114) ... 

What attractive interaction occurs in nonpolar substances To leant the answer to this question, consider the arrangement shown in Figure 11.4. If we place an ion or a polar molecule near an atom (or a nonpolar molecule), the electron distribution of the atom (or molecule) is distorted by the force exerted by the ion or the polar molecule, resulting in a kind of dipole. The dipole in the atom (or nonpolar molecule) is said to be an induced dipole because the separation of positive and negative charges in the atom (or nonpolar molecule) is due to the proximity of an ion or a polar molecule. The attractive interaction between an ion and the induced dipole is called ion-induced dipole interaction, and the attractive interaction between a polar molecule and the induced dipole is called dipole-induced dipole interaction. 

Liquid-Liquid and Solid-Liquid Solutions Many salts dissolve in water because the strong ion-dipole attractions that water molecules form with the ions are very similar to the strong attractions between the ions themselves and, therefore, can substitute for them. The same salts are insoluble in hexane (CgH ) because the weak ion-induced dipole forces their ions could form with the nonpolar molecules of this solvent cannot substitute for attractions between the ions. Similarly, oil does not dissolve in water because the weak dipole-induced dipole forces between oil and water molecules cannot substitute for the strong H bonds between water molecules. Oil does dissolve in hexane, however, because the dispersion forces in one substitute readily for the dispersion forces in the other. Thus, for a solution to form, like dissolves like means that the forces created between solute and solvent must be comparable in strength to the forces destroyed within both the solute and the solvent. 

Ionic interactions— Another class of intermolecular attractions involves attractive and repulsive forces between pairs of ions, or between ions and neutrally charged atoms or molecules. These interactions are typically stronger than those in the Van der Waal s category. Interactions between pairs of ions are governed by Coulomb s law, while interactions between ions and neutral molecules are either ion-dipole or ion-induced dipole interactions. 

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