Ion-dots

Fig. 2 Hydrogen bond geometry (not to scale) + and - are positions 5/2 and - 5/2, respectively. P and S are P04 core and shell is the potassium ion dotted lines indicate the contributions to C(5)...

Two-dimensional, metal-containing grids are of particular interest as their structures suggest the basis for the construction of information storage devices. Arrays on this type, in which the metal ions act as ion dots that might prove accessible by external stimuli, would be of smaller size than quantum dots. They have the potential advantage of self-assembling spontaneously and hence may eliminate the need for microfabrication. ... 

Two-dimensional grid-like structures are of particular interest, as their architectures may serve as a basis for the construction of information storage devices (33). By addressing the metal ions photo- or electrochemically, it might be possible to inscribe into the arrays patterns which could be read out non-destructively (7). Such ion dots would still be of smaller size than quantum dots (34), and they would form spontaneously by self-assembly, not requiring microfabrication. 

Fig. 6. 24 A depiction of the X-ray structure of Ca-BFl. The right part of the protein is the kringle-domain, where the solvent inaccessible tryptophan residues Trp90 and Trpl26 are located. The Gla-domain is the left part of the protein, containing the solvent and quencher accessible Trp42 and seven calcium ions (dots).

Fig. 7. DD-MAS (A and C) and CP-MAS (B and D) NMR spectra of the [l- C]Gly and Leu-labeled bR from PM, respectively, without (solid traces) and with 40 pM Mn ion (dotted traces). " Reproduced with permission from John-Wiley and Son, Ltd.

Fig. 25. CP-MAS NMR spectra of the [3- C]Ala-labeled wild type (A), E204Q (B), and E204D (C) mutants. All spectra were recorded in the presence of 40 pM Mn ion. Dotted spectra in the traces B and C are from 40 pM Mn -treated wild type. Reproduced with permission from the lOS Press.

Fig. 3 The densities for the hydrocarbon (solid), head-group (dot-dashed), Na ion (dotted) and water (dashed) with respect to the center of mass of the column for the NP (a), PS (b), and FP (c) models...

Fig. 15. Heulandites. Cation bonding distances of extra-framework metal ions. Dotted lines (triangles), represent M-H2O distances in the [M(H20)g] complex. Solid lines (filled circles) are average bond distances between the B site and oxygen of the tetrahedral framework. Dashed lines are mean bonding distances between the A1 site and oxygen of the tetrahedral framework [03G1].

Fig. SA Potential-energy curves for H2 calculated in a minimal basis of hydrogenic I j functions with unit exponents (atomic units). The closed-shell two-configuration ground and excited states are represented by thick grey lines and the dashed lines represent the open-shell (lower curve) and (upper curve) states. Also depicted are the energy curves of the single-configuration bonding and antibonding states Icr ) and (T > (thin full lines) as well as of the covalent and ionic states cov) and ion) (dotted lines).

Free Radicals. In the formula of a polyatomic radical an unpaired electron(s) is(are) indicated by a dot placed as a right superscript to the parentheses (or square bracket for coordination compounds). In radical ions the dot precedes the charge. In structural formulas, the dot may be placed to indicate the location of the unpaired electron(s). 

A typical cascade process. A fast atom or ion collides with surface molecules, sharing its momentum and causing the struck molecules to move faster. The resulting fast-moving particles then strike others, setting up a cascade of collisions until all the initial momentum has been redistributed. The dots ( ) indicate collision points, tons or atoms (o) leave the surface. 

In (a), a pulse of ions is formed but, for illustration purposes, all with the same m/z value. In (b), the ions have been accelerated but, because they were not all formed in the same space, they are separated in time and velocity, with some ions having more kinetic energy than others. In (c), the ions approach the ion mirror or reflectron, which they then penetrate to different depths, depending on their kinetic energies (d). The ones with greater kinetic energy penetrate furthest. In (e), the ions leave the reflectron and travel on to the detector (f), which they all reach at the same time. The path taken by the ions is indicated by the dotted line in (f). 

If digital voltage readings (V1-V9) are taken at time intervals (At = 0.0001 sec in the example of Figure 44.4), then the area of the true peak (dotted) can be (mathematically) closely approximated to give ion abundance and, similarly, the time (tj to the center of gravity (centroid) of the peak can be determined, thereby giving the m/z value. 

Radical ion. An ion containing an unpaired electron that is thus both an ion and a free radical. The presence of the odd electron is denoted by placing a dot alongside the symbol for the charge. Thus, and SF are radical ions. 

Here Oq represents the oxide ion which is incorporated, IT represents the Ni + ion which is a positive hole, and an exU a negative charge being indicated by the superscript dot, thus V/,j is the vacant cation site where tire double dot represents the absence of two positive charges at that site. 

Fig. 3.64. H depth profile of an H-im-planted Si sample obtained with 6-MeV C projectile ions for different recoil angles 9. q gives the charge ofthe incident ions. The experimental depth profiles (full line) are compared with simulated spectra (dashed line-SIMNRA, dotted line - DEPTH) [3.177].

Let us choose now a particular solvent and a particular ionic crystal. If by the process (1,M) we obtain in a vacuum the ions from this crystal, and if we then imagine that we plunge these ions into the chosen solvent, as indicated by the vertical dotted arrow in Fig. la, it is clear that the... 

Lewis structure An electronic structure of a molecule or ion in which electrons are shown by dashes or dots (electron pairs), 166-167,192q formal charge, 171-172 nonmetal oxides, 564-565 oxoacids, 567 resonance forms, 170-171 writing, 168-169 Libby, Willard, 174... 

In the most extreme situation, the bonding electrons move so close to one of the atoms that this atom has virtually the electron distribution of the negative ion. This is the case in gaseous LiF. In an electron dot representation, we might show... 

Draw an electron dot representation for the NHj" ion. What shape do you predict this ion will have ... 

Fig. 2-3. Number of electrons produced at various detector voltages for each x-ray quantum absorbed. A quantum of 1-A wavelength produces 400 ion pairs directly (solid line). A quantum of 10-A wavelength produces directly only 40 ion pairs (dotted line). (After Wilkinson, Ionization Chambers and Counters, University Press, Cambridge.)...

The photolysis of arenediazonium salts has been widely used for intramolecular cyclizations in the synthesis of 1-phenylethylisoquinoline alkaloids by Kametani and Fukumoto (review 1972). An example is the photolysis of the diazonium ion 10.73, which resulted in the formation of O-benzylandrocymbine (10.74) (Kametani et al., 1971). The mechanism of this cyclization is obviously quite complex, since the carbon (as cation or radical ) to which the diazonio group is attached in 10.73 does not react with the aromatic CH group, but with the tertiary carbon (dot in 10.73), forming a quinone-like ring (10.74). In our opinion the methyl cation released is likely to react with the counter-ion X- or the solvent. 

The absolute (a) and relative (b) amounts of Pu(IV) hydroxide ion concentration (or pH), calculated by Equation 4 based on the data given in Table I. The region of interest for the present investigation is marked by dotted lines. 

Figure 11. Schematic diagram of anodic polarization curve of passive-metal electrode when sweeping electrode potential in the noble direction. The dotted line indicates the polarization curve in the absence of Cl-ions, whereas the solid line is the polarization curve in the presence of Cl ions.7 Ep, passivation potential Eb, breakdown potential Epit> the critical pitting potential ETP, transpassive potential. (From N. Sato, J, Electrochem. Soc. 129, 255, 1982, Fig. 1. Reproduced by permission of The Electrochemical Society, Inc.)...

FIGURE 2.6 The arrangement used to calculate the potential energy of an ion in a line of alternating cations (red spheres) and anions (green spheres). We concentrate on one ion, the "central ion denoted by the vertical dotted line. 

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