Download or read book Second Harmonic Generation as a Surface Probe written by Heung-Rae Lee and published by . This book was released on 1990 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Second harmonic Generation as a Surface Probe for Colloidal Particles written by Elsa Chui-Ying Yan and published by . This book was released on 2000 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Studies on Second harmonic Generation as a Surface Probe written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical second-harmonic generation (SHG) is sensitive enough to respond to a submonolayer of surface atoms or molecules. It can therefore be used to probe surfaces or interfaces between two centrosymmetric media. The surface-specific nature of this optical method offers some advantages. We have demonstrated in recent experiments that resonant SHG can allow us to obtain spectroscopic data of submonolayers of adsorbed molecules on a surface. The signal was so strong that less than one tenth of a monolayer of dye molecules could be easily detected. The method can be applied to molecules adsorbed at an interface between two dense media such as a liquid/solid interface. Then, using SHG, adsorption isotherms of adsorbates on substrates can be measured. One is often interested in how large the bulk contribution to SHG is in comparison with the surface contribution. Second-order nonlinear optical processes are forbidden in a medium with inversion symmetry only in the electric-dipole approximation. Could SGH from electric-quadrupole and magnetic-dipole contributions in the bulk be so strong as to mask out the electric-dipole contribution from the surface. We have found that the SH signal from a centrosymmetric substrate can be changed appreciably by the adsorption of a monolayer. This clearly indicates that it is the adsorbate layer rather than the bulk of the substrate which dominates the SHG process. We are, however, also interested in developing the SHG technique for studying bare surfaces, and would like to know the relative bulk and surface contribution to SHG in such cases. We have studied this problem experimentally by measuring the SHG from well-defined faces of a crystalline material.
Download or read book Optical Second Harmonic Generation and Infrared Visible Sum Frequency Generation as Surface Probes written by Philippe Marie Guyot-Sionnest and published by . This book was released on 1987 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Surfaces Using Optical Second harmonic Generation written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The experiments reported in this thesis demonstrate the use of second-harmonic generation (SHG) and sum-frequency generation (SFG) in reflection from surfaces to study various surface properties. The experiments firmly establish SHG as a viable new surface probe that complements existing surface probes in ultrahigh vacuum environments and is in many ways unique for studying interfaces between dense media. Surface structural symmetry can be revealed through the anisotropy in the SH signal from the surface as the sample is rotated about its normal. The form of this anisotropy is derived in theory and verified with an experiment on the Si(100) and (111) surfaces. The SHG and SFG signals from molecules adsorbed on noninteracting substrates have a direct relationship to the number, average orientation, and spectroscopic properties of the molecules. The SH intensity was used to measure the isotherm for adsorption of p-nitrobenzoic acid from ethanolic solution to fused silica. Experiments performed on a strongly-interacting well-characterized Rh(111) surface in ultrahigh vacuum establish the sensitivity of the SH probe in corroboration with other surface probes. For the first time, the SH coverage-dependence was fit by theory in a quantitative way for the case of O-atom adsorption. The sensitivity of SH to adsorption at different sites was established for CO on top- and bridge-sites. SHG was shown to be surface specific in that the SHG from alkali metal surfaces originates from the first two monolayers. SH sensitivity to the adsorption of catalytically-important hydrocarbons and to chemical processes such as benzene dehydrogenation was also demonstrated. 122 references, 27 figures, 2 tables.
Download or read book Second Harmonic Generation Imaging written by Francesco S. Pavone and published by Taylor & Francis. This book was released on 2016-04-19 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Second-harmonic generation (SHG) microscopy has shown great promise for imaging live cells and tissues, with applications in basic science, medical research, and tissue engineering. Second Harmonic Generation Imaging offers a complete guide to this optical modality, from basic principles, instrumentation, methods, and image analysis to biomedical a
Download or read book Studies of Surfaces Using Optical Second harmonic Generation written by Harry W. K. Tom and published by . This book was released on 1984 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Second Harmonic Generation as an Interfacial Probe written by Dirk Campbell DeMott and published by . This book was released on 1986 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Second Harmonic Generation and Sum Frequency Generation written by and published by . This book was released on 1990 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Second harmonic generation and sum frequency generation are increasingly being used as in situ surface probes. These techniques are coherent and inherently surface sensitive by the nature of the mediums response to intense laser light. Here we will review these two techniques using aqueous corrosion as an example problem. Aqueous corrosion of technologically important materials such as Fe, Ni and Cr proceeds from a reduced metal surface with layer by layer growth of oxide films mitigated by compositional changes in the chemical makeup of the growing film. Passivation of the metal surface is achieved after growth of only a few tens of atomic layers of metal oxide. Surface Second Harmonic Generation and a related nonlinear laser technique, Sum Frequency Generation have demonstrated an ability to probe the surface composition of growing films even in the presence of aqueous solutions. 96 refs., 4 figs.
Download or read book Laser Spectroscopy VII written by Theo W. Hansch and published by . This book was released on 2014-01-15 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Second Harmonic Generation as a Probe of Molecular Adsorption and Orientation in Monolayer Films at Condensed phase Interfaces written by Daniel Alfred Higgins and published by . This book was released on 1993 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Application of the Symmetry Properties of Optical Second Harmonic Generation to Studies of Interfaces and Gases written by and published by . This book was released on 1991 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical second harmonic generation has proven to be a powerful tool for studying interfaces. The symmetry properties of the process allow for surface sensitivity not available with other optical methods. In this thesis, we take advantage of these symmetry properties SHG to study a variety of interesting systems not previously studied with this technique. We show that optical second harmonic generation is an effective surface probe with a submonolayer sensitivity for media without inversion symmetry. We demonstrate the technique at a gallium arsenide surface, exploiting the different symmetry properties of the bulk and surface of the crystal to isolate the surface contribution. We also demonstrate that optical second harmonic generation can be used to determine the anisotropic orientational distribution of a surface monolayer of molecules. We apply the technique to study homogeneously aligned liquid crystal cells. To further explore the LC-polymer interface, we used SHG to study the surface memory effect. The surface memory effect is the rendering of an isotropic interface anisotropic by putting it in contact with an anisotropic bulk. Last, we describe some preliminary measurements of a time-resolved spectroscopic study of the phenomenon of second harmonic generation in a gas. The construction of a 500 microjoule pulsed, tunable laser source is described.
Download or read book Second Harmonic Generation as a Probe of Molecular Orientation at Interfaces written by Shannon Kathleen Byerly and published by . This book was released on 1990 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Second harmonic and Sum frequency Generation for Surface Studies written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Second harmonic generation (SHG) has now been well established as a versatile surface-sensitive probe. It has been used to study electrochemical processes at electrode surfaces, molecular adsorption and desorption at metal and semiconductor surfaces, orientational phase transition of molecular monolayers on water, surface reconstruction and epitaxial growth, and so on. More recently, it has been employed as a tool to monitor monolayer polymerization and other surface reactions, to probe polar order of molecules at interfaces, and to measure molecular nonlinearity. While most surface techniques are restricted to the solid/vacuum environment, SHG is applicable to nearly all interfaces as long as the interfaces are accessible by light. In addition, SHG has the advantages of being capable of in-situ measurements with high temporal, spatial, and spectral resolutions.
Download or read book Second harmonic Generation as a Probe of Chemically Modified Si 111 Surfaces and the Initial Oxidation of Hydrogen Terminated Si 111 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book LBL Research Review written by and published by . This book was released on 1985 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photonic Probes of Surfaces written by P. Halevi and published by Newnes. This book was released on 2012-12-02 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is devoted principally to optical spectroscopies of material surfaces and also encompasses scattering techniques and theoretical response analysis as well as spectroscopies. In addition to solid surfaces some attention is also devoted to interfaces between two solids, between a solid and a liquid and to a liquid-vapor interface. These surfaces may be clean and perfect, in which case the purpose of the spectroscopical method at hand is to determine the deviation of the atomic structure in the surface region from that in the bulk, namely the surface reconstruction. Otherwise the surface may be imperfect due to roughness, strain or overlayers, in which case the spectroscopy can yield information on the nature of such imperfections, including the monitoring of growth processes. One of the foremost purposes of surface spectroscopies is to extract information on atomic and molecular adsorbates on solid surfaces. Most of the 10 chapters are concerned with photonic sources of excitation, the respective spectral regions ranging from the far infrared to X-rays.In conclusion this book provides a state-of-the-art review of all major types of photonic probes of surfaces and interfaces and deals with both applications and experiment and theory.
