Self-focussing

The discovery of self-focussing of intense laser beams 318 ) and the phenomena of self-induced transparency 318b) have stimulated a whole new class of experimental investigations which give information about the transient interaction between light and matter 318c)... 

Since the refractive index of glass is increased by intensive laser radiation given by the non-linear refractive index n2 (n = no + n2 , with no = index in absence of intense radiation, E = the electric field strength of the light beam) its magnitude should be as small as possible to avoid self-focussing of the laser beam. 

V.E. Zakharov, A.B. Shabat, Exact theory of two-dimensional self-focussing and onedimensional self-modulation of waves in nonlinear media. Sov. Phys. JETP 37,823 (1973)... 

Zel dovich BY, Tabiryan NV (1980) Light self-focussing in nematic liquid crystals as a method of investigation of the fi ee surface orienting influence. Sov Phys JETP 52 1210 ZeTdovich BY, Tabiryan NV, Chilingaryan YS (1981) Fredericks transitions induced by light fields. Sov Phys JETP 54(l) 32-37... 

The ability of XB to control recognition, self-organization, and self-assembly processes in the different phases of matter is clearly emerging in the literature. This chapter focusses on self-assembly in the solid phase, while the chapters of B. Duncan and A. Legon (in this volume) deal with the liquid crystalline phase and gas phase, respectively. Relatively few papers are reported in the literature on self-assembly processes in solution [66-68,207,208]. Several analytical techniques have been used to detect XB formation, to define its nature, to establish its energetic and geometric characteristics, and to reveal... 

Synthetic efforts at preparing model complexes for the FeMo-cofactor have largely focussed on two types of Mo-Fe-S cluster, both of which are prepared via self-assembly reactions using tetrathiomolybdate as starting material. The first of these is the "linear" type of cluster, containing the MoS2Fe unit formed by coordination of discrete MoS - units to Fe. The second is the... 

When an intense pulse of monochromatic laser light is focussed on a transparent liquid or solid, there is an emission of white light over a wide continuous spectral range. This process is known as self-phase modulation . We will not consider its physics. For our purpose it is important to note its photochemical implications. On the one hand, this pulse of white light can be used to provide a probe light in ps and fs flash photolysis (sections 8.1 and 8.2). On the other hand, it can be a source of stray light in some luminescence measurements. This comes as a surprise to many users of lasers for luminescence kinetics measurements, but it is an unavoidable problem. 

Netropsin complexes with nucleic acids have been monitored by spectroscopic techniques at the oligomer duplex and DNA level (89-96). Our research focussed on the application of high resolution NMR spectroscopy to elucidate structural and dynamic aspects of netropsin complexes with the self-complementary octanucleotide dG-dG-dA-dA-dT-dT-dC-dC duplex (9 7) and the synthetic DNA poly(dA-dT) (27) in aqueous solution. 

As an illustration of the second approach to biosynthesis, the work of Boden et al. will be taken as an example. Again the first step is to identify an interesting motif to be incorporated in a molecule. The motif that they have focussed on is the P-sheet. By incorporating a sequence which facilitates the formation of this structure it becomes possible to form a peptide which spontaneously self-assembles into P-sheet tapes. In appropriate solvents these peptides can form gels whose rheological properties can then be controlled by external parameters such as pH. Thus, what they have termed rational design coupled with the peptide synthesiser may yield macromolecules with a specific set of controlled properties. 

The Marcus Theory can also be applied for heterogeneous electron transfer reaction at electrode surfaces [24 and references therein]. The electronic coupling between the protein and the electrode can be varied using different self-assembled monolayers controlling the orientation of the redox active protein on the surface and the distance between the redox active site of the protein and the electrode. The driving force is related to the appHed potential and the redox potential of the protein. In many cases the rate of electron transfer across the protein-electrode interface is limited by conformational reorganization. This has focussed the efforts of many groups on tailored interaction between proteins and enzymes and electrode surfaces. 

The theory of van der Waals (vdW) surface interactions is presented here in terms of correlation-self energies of the constituent parts involved in the interaction due to their mutual polarization in the electrostatic limit. In this description the van der Waals interactions are exhibited using the dynamic, nonlocal and inhomogeneous screening functions of the constituent parts. In regard to the van der Waals interaction of a single molecule and a substrate, this problem is substantially the same as that of the van der Waals interaction of an atom and a substrate, in which the atomic aspects of the problem are subsumed in a multipole expansion based on spatial localization of the atom/molecule. As we (and others) have treated this in detail in the past we will not discuss it further in this paper. Here, our attention will be focussed on the van der Waals interaction of an adsorbate layer with a substrate, with the dielectric properties of the adsorbate layer modeled as a two-dimensional plasma sheet, and those of the substrate modeled by a semi-infinite bulk plasma. This formulation can be easily adapted to an... 

This contribution as a chapter in the special volume of ADVANCES IN QUANTUM CHEMISTRY on Confined Quantum Systems is focussed on (i) the hydrogen atom, (ii) confinement by conoidal boundaries, and (iii) semi-infinite spaces however, some of its discussions may extend their validity to other physical systems and to confinement in closed volumes. The limitations in the title are given as a point of reference, and also take into account that several of the other chapters deal with confinement in finite volumes. A semantic parenthesis is also appropriate and self-explanatory Compare conical curves (circles, ellipses, parabolas, hyperbolas and their radial asymptotes) with conoidal surfaces (spheres, spheroids, paraboloids, hyperboloids and their radial asymptotic cones). 

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