Induced local modification

The discussion above shows that TCV can be reasonably interpreted in the framework of known electronic states. The direct determination of interface states from TCV seems difficult because the dependence of (7° with the tip potential [78, 81] finds no simple explanation within a simple one-dimensional energy diagram. Tip-induced local modifications of the band diagram of the semiconductor may exist (see Sec. 4.2.3) which complicates the determination of energy levels. The experimental dependence of [7° on the pre-history of the electrode [78, 81] stem probably from... 

The chemistry of the selective-surface metallization process has taken two paths. One approach (53) involves photo-induced local modifications in... 

When we will discuss the effects of solvent collapse in solute-solvent interactions (section 8.11.2), we will mean local modifications of the water structure (degree of distortion of the oxygen bond distance between neighboring oxygen nuclei) induced by the presence of electrolytes in solution. We refer to the classical text of Eisemberg and Kauzmann (1969) for a more detailed discussion on the various aggregation states of the H2O compound. 

First-principles calculations of an STM, including a real tip and a real sample, clearly show that within the normal tip-sample distances (3.-6 A from nucleus to nucleus), in the gap region, the local electronic density resembles neither that of the tip nor that of the sample. Substantial local modifications are induced by the strong interaction. An example is the system of an A1 sample with an A1 tip, calculated by Ciraci, Baratoff, and Batra (1990a), as shown in Fig. 8.1. As the tip-sample distance is reduced to 8 bohr, the electron density begins to show a substantial concentration in the middle of the gap. This phenomenon becomes much more pronounced when the tip-sample distance is reduced to about 7 bohr. These distances are exactly the normal distances where atom-resolved images are obtained. 

This effect can be illustrated by Fig. 14.2. The effective range of local modification of the sample states is determined by the effective lateral dimension 4ff of the tip wavefunction, which also determines the lateral resolution. In analogy with the analytic result for the hydrogen molecular ion problem, the local modification makes the amplitude of the sample wavefunction increase by a factor exp( — Vi) 1.213, which is equivalent to inducing a localized state of radius r 4tf/2 superimposed on the unperturbed state of the solid surface. The local density of that state is about (4/e — 1) 0.47 times the local electron density of the original stale in the middle of the gap. This superimposed local state cannot be formed by Bloch states with the same energy eigenvalue. Because of dispersion (that is, the finite value of dEldk and... 

The behaviour of the phonons can be related to pressure induced structural modifications. Unfortunately, for the Y123 compounds, the variation of the bond lengths as a function of pressure has been studied only for low pressures, up to 0.56 GPa [23] and there are no data available for an independent verification of the predictions of local structural modifications. The structural hydrostatic pressure measurements have found a similar pressure dependence of the a- and c-axes for the underdoped and overdoped Y123, while, for the b axis, the underdoped exhibits a larger compression ( 20%) than the overdoped sample [23], The Raman data for low pressures... 

It is also possible that the properties of the solution induce some modifications of eq. (17). This is the case for example of a fluorescent probe attached onto a polyelectrolyte in this case, the high local concentration of ions strongly influences the rate constant so that eq. (17) is no longer valid. For one typical recent example of such a phenomenon with phenanthrene, see Morrison et al. (1996). 

LOCAL MODIFICATION OF SURFACES INDUCED BY ADSORBED MOLECULES... 

Part V Local Modification of Surfaces Induced by Adsorbed Molecules... 

The fact that binding of progesterone on a i-acid glycoprotein induces a modification of the local structure and the dynamics of the protein indicates that these modifications are important for the binding of the ligand. 

Also, it will be possible to measure the fluorescence anisotropy decay at certain wavelengths that are specific to one class of fluorophore but not the other. The decay measurements performed on a protein where the surface Trp residue is oxidized, would give information on the dynamics of the buried Trp residues. This is true if oxidation of the Trp residue surface did not induce any modification in the local or/and global structure and dynamics of the protein. 

Following the penetration of the cell membrane, corticoids bind with specific cytoplasmic receptors. These receptors have been demonstrated in all target tissues including the skin [4, 17]. After modification, the steroid-receptor complex enters the nucleus, where it interacts with DNA to alter the production of mRNA induced locally by RNA polymerase. This mRNA moves into the cytoplasm, where it attaches to ribosomes and acts as a template for protein synthesis. 

Yumura, T., Kertesz, M., lijima, S. (2007). Local modifications of single-wall carbon nanotubes induced by bond formation with encapsulated... 

When a laser pulse passes through a material it produces a local non equilibrium state that induces a modification of the optical properties. This is a transient effect that relaxes back to the equilihrium state through a variety of processes. In a typical pump-prohe experiment, a second laser pulse is sent on the material probing the optical modifications induced by the pump pulse. Since the second laser pulse arrives with a controlled delay, it monitors and measures the transient optical excitation and hence the relaxation of the nonequilibrium state. In the time-resolved OKE both the pulses, pump and probe, are linearly... 

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