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The extrema

For the compound Ap which reacts according to the mechanism, eq. (2.75), the maximum concentration amounts to [Pg.96]


For a simple bistable reaction potential, it is clear that maximum curvamre along the reaction pathway will occur near the extrema—the minima and the barrier top. The path endpoints are typically chosen to sit in the reactant and product minima, and in such a case the maximum error will result from the path straddling the barrier top as in Figure 8. Of course, this is the error made in a single segment of the pathway. For a general potential the pathway will consist of multiple segments and may have many barriers. [Pg.216]

PL is generally most usefril in semiconductors if their band gap is direct, i.e., if the extrema of the conduction and valence bands have the same crystal momentum, and optical transitions are momentum-allowed. Especially at low temperatures. [Pg.376]

The antisymmetric stretching vibration. The molecule loses its original symmetry during the vibration. At the two extrema of the vibration the shapes of the molecule will be identical. Because the molecular polarizability is essentially the summation of all bond polarizabilities and is independent of direction along the internuclear axis, it will have identical values at the extrema. Consequently, the vibration is Raman inactive. [Pg.301]

A wavelet defined as above is called a first-order wavelet. From Eq. (21) we conclude that the extrema points of the first-order wavelet transform provide the position of the inflexion points of the scaled signal at any level of scale. Similarly, if i/ (f) = d it)/dt, then the zero crossings of the wavelet transform correspond to the inflexion points of the original signal smoothed (i.e., scaled) by the scaling function, tj/it) (Mallat, 1991). [Pg.240]

A very similar application of the modified Bloch equations was based in the work of Adams and Connelly.4 ESR spectra (Figure 5.8) of [Mo P(0 Me)3 2(MeC = CMc)Cp] show the expected triplet (two equivalent 31P nuclei) at 280 K, but only a doublet at 160 K. At intermediate temperatures, the lines broaden. The interpretation is that the alkyne undergoes a pendulum oscillation, which in the extrema diverts spin density from one or the other phosphite. Interestingly, the diamagnetic cation undergoes a similar motion on the NMR time scale, but then the alkyne undergoes a complete rotation. Thus, analysis of the effect leads to a measure of the rate of the oscillation. The... [Pg.104]

Once the total entropy of a composite system has been formulated as a function of the various extensive parameters of the subsystems, the extrema of this total entropy function may in principle be located by direct differentiation and classified as either maxima, minima or inflection points from the sign of the second derivative. Of these extrema, only the maxima represent stable equilibria. [Pg.411]

To attain a transverse field profile that is confined within the defect, the profile must exponentially increase for p < pdef, and exponentially decrease for p > pdef. This requirement determines which index-interfaces (lowhigh or highlow) should be positioned at zeros of the field and which at the extrema of the field. The constraints on the index profile are similar to the Cartesian case and differ for the TE and TM polarizations. For the TE polarization, the interfaces for decreasing (increasing) field should be at the zeros (extrema) of If, if nip ) > n(p 1) at the interface and at the extrema (zeros) of Hz if nip ) < nip 1) at the interface. For the TM polarization, the interfaces for decreasing (increasing) field should be at the extrema (zeros) of E, if n(p ) > n(p+) at the interface and at the zeros (extrema) of E, if n(p ) < nip 1) at the interface. The interfaces of the defect must be located at zeros of II, for TE and of E, for TM. [Pg.321]

These quantities indicate the variability of the positive, negative, and total surface potentials, i.e., Vs (r,), Vs (r,-), and Vs(r). Due to the terms in Equation 17.10 being squared, the variances are particularly sensitive to the extrema of Vs(r), Vs.max, and Vs>min-It may seem that there is some similarity between ofot and II, but in fact the former is normally much larger in magnitude and they may not even show the same trend in a series of molecules [43]. [Pg.251]

By forming the maxima or minima respectively of these quantities, the extrema being taken over all r with zf 0, we get chirality numbers which are characteristic properties of the skeleton. It should be emphasized that the condition is zfV 0 and not zr 0 because the latter would only lead to trivial numbers which express the fact that a ligand partition is active for any achiral frame if it contains at least one chiral ligand. The nontrivial numbers we want should present information about the pseudoscalar properties of the particular molecular class in question. We find these chirality numbers from the following maxima and minima ... [Pg.67]

The extrema of Vs(r) are, however, only the beginning of the useful information that can be gleaned from it. The question is how to characterize the key features and overall pattern of Vs(r) sufficiently to permit quantitative correlations with physical properties. Over a period of several years, we have identified a group of statistically-defined quantities that are effective for this... [Pg.24]

The variances indicate the variabilities, or ranges, of the positive, the negative and the overall electrostatic potentials on the molecular surfaces. They are particularly sensitive to the extrema, Vs,max and Vs,min, due to the terms being squared. This also means that they may be much... [Pg.25]

According to Fig. 5 the maximum and minimum in the NACME to the first excited state produce a minimum and maximum in the corresponding contribution to the electronic contribution to the vibrational g factor. The extrema are at the same internuclear distances and have positions near the extrema in the total electronic contribution to g R), but are not as steep. The contributions from the second, third, and up to the fifth excited states modify slightly the position and the form of the extrema but introduce no fundamental modification. We, therefore, conclude that the extrema in the vibrational g factor reflect extrema in the first-order NACME to the first excited state, and not in the energy of the excited state. The exact position of the minimum in the vibrational g factor is, however, influenced by more highly excited states. [Pg.332]

As it is well known, stationary solutions to Eq.(3.2) occur at the extrema of the Hamiltonian for a given power. The solutions that correspond to global or local minimum of H for a family of solitons are stable. The representation of the output nonlinear waveguide as a nonlinear dynamical system by the Hamiltonian allows to predict, to some extent, the dynamics of the total field behind the waveguide junction. [Pg.162]

Strong evidence of the dominant Influence of molecular conformation on the properties of coals Is Implicit In the several data sets which show an extremum In the measured property when plotted against carbon rank. Examples are the extrema which occur In the solid state properties of mass density (22,23) and proton spin-lattice relaxation rate (24) as well as In solvent swelling and extractablllty ( ). [Pg.113]

The Ni surfaces used in these experiments were nominally within 1 of (100) and (110) so that they undoubtedly had a fairly large density of the type of background steps described in figure 1. The temperature range used may have sparmed that of terrace roughening but the presence of so many steps due to the miscut probably masked any effect of spontaneous step creation on the terraces. Under such experimental conditions it is extremely unlikely that extensive facets at the extrema have strong effects on the mode of decay. [Pg.26]

Figure 7. STM4 image showing the crossing steps(due to the miscut ) at a maximum of a 1-D grating on a surface near Si(OOl). Due primarily to the difference in free energies of the two step types they occur in pairs[28]. It is believed that the amplitude decay occurs by the motion of such crossing steps along the extrema. Figure 7. STM4 image showing the crossing steps(due to the miscut ) at a maximum of a 1-D grating on a surface near Si(OOl). Due primarily to the difference in free energies of the two step types they occur in pairs[28]. It is believed that the amplitude decay occurs by the motion of such crossing steps along the extrema.
Much of the data from these recent LEEM studies is currently being analysed. We give here a brief discussion of i) the kinetics of the island/hole development at the extrema at 950C, ii) the effects of evaporation on the... [Pg.33]


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