Anomalous mobility

One can pick up a clue as to the reason for this anomaly in mobility if one asks What is the proton s mobility in other, related solvents This rather vital question was addressed and solved in a Ph.D. thesis by an Austrian student, Hanna Rosenberg, more than 40 years ago. She foimd that if, for example, methanol was added to water, the anomalous mobility of the proton was decreased (Fig. 4.120). When methanol was replaced by other, larger alcohols (no water present), she was astounded to find that the anomalous mobility was greatly reduced until by the time n-propanol was reached, the difference between HCI and LiCl was greatly reduced (Table 4.29). 

The decrease in anomalous mobility of the proton in the presence of added alcohol solvents (see Section 4.11.2) could also be explained the larger size of the alcohol makes its reorientation more difficult than that for water and causes a fall in proton mobility by the tunneling and solvent-oriented method. 

Gierer, A., and Wirtz, K. 1949. Anomale H-ioncnbewegUchkeit und OH-ionenbewegUchkeit im wasser. (Anomalous mobility of H and OH ions in water). Annalen Phys., 6, 257-304. 

N is the Avogadro number, and k is a constant. The value of k may be estimated[382] from the diffusion coefficient of HaO , D - 5 x 10 cm s" and the length of the diffusion jump A - 3 x 10 cm (in order of magnitude, A is the distance between two oxygen atoms connected through a hydrogen bond, and the mechanism of anomalous mobility of the hydrogen ion is considered in this case)... 

Figure 10. Isotherms of internal mobilities in various binary nitrates containing Ag as one cation. (Reprinted from I. Okada and P.-H. Chou, Anomalous Behavior of Internal Mobilities for Ag(I) and T1(I) Ions in Molten Nitrates, J. Electrochem. Soc. 144 (4) 1333, 1997, Fig.2. Reproduced by permission of the Electrochemical Society, Inc.)...

To fully understand the anomalous dynamics of an attractive colloidal fluid from a free-volume perspective, one must consider two effects of attractions on free volumes.75 First, attractions increase the average local space available to the particles and render the free-volume distribution more inhomogeneous than when no attractions exist. These changes act to increase the mobility of the fluid. Second, strong attractions also lead to long-lived... 

The anomalous Na decrease with depth in Figure 4 illustrates a problem with ion team profiling in that some light ions, including Na, are mobile under the beam and can be stripped from the surface or embedded deeper in the matrix. K ions do not appear to be susceptible to this phenomenon and heavier elements such as Rb, Cs and Sr would be expected to be even less affected. Profiles of Si and Al, although not shown in Figure 4, were essentially constant with depth documenting the lack of secondary mineral formation on the surfaces of the obsidian and feldspar. 

Metal to insulator Semiconductor to insulator, or Insulator to insulator Light contact (touching) Ion migration (due to inherent or unavoidable ion contamination electron traps (a) by random adhesion of ions for contact of dissimilar materials (b) by diffusion due to differences in ion concentration or mobilities (c) by image attraction Anomalous (due to avoidable surface contamination)... 

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