Studies of Surfaces Using Optical Second-harmonic Generation PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Studies of Surfaces Using Optical Second-harmonic Generation PDF full book. Access full book title Studies of Surfaces Using Optical Second-harmonic Generation by Harry W. K. Tom. Download full books in PDF and EPUB format.
Author: Harry W. K. Tom
Publisher:
ISBN:
Category :
Languages : en
Pages : 322
Get Book Here
Book Description
Author: Harry W. K. Tom
Publisher:
ISBN:
Category :
Languages : en
Pages : 322
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
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.
Author: Yong Qiang An
Publisher:
ISBN:
Category : Polarization spectroscopy
Languages : en
Pages : 254
Get Book Here
Book Description
Author: Francesco S. Pavone
Publisher: Taylor & Francis
ISBN: 1439849153
Category : Science
Languages : en
Pages : 465
Get Book Here
Book Description
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
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Get Book Here
Book Description
The possibly of using nonlinear optical processes for surface studies has attracted increasing attention in recent years. Optical second harmonic generation (SHG) and sum frequency generation (SFG), in particular, have been well accepted as viable surface probes. They have many advantages over the conventional techniques. By nature, they are highly surface-specific and has a submonolayer sensitivity. As coherent optical processes, they are capable of in-situ probing of surfaces in hostile environment as well as applicable to all interfaces accessible by light. With ultrafast pump laser pulses, they can be employed to study surface dynamic processes with a subpicosecond time resolution. These advantages have opened the door to many exciting research opportunities in surface science and technology. This paper gives a brief overview of this fast-growing new area of research. Optical SHG from a surface was first studied theoretically and experimentally in the sixties. Even the submonolayer surface sensitivity of the process was noticed fairly early. The success was, however, limited because of difficulties in controlling the experimental conditions. It was not until the early 1980's that the potential of the process for surface analysis was duly recognized. The first surface study by SHG was actually motivated by the then active search for an understanding of the intriguing surface enhanced Raman scattering (SERS). It had been suspected that the enhancement in SERS mainly came from the local-field enhancement due to local plasmon resonances and pointing rod effect on rough metal surfaces. In our view, Raman scattering is a two-photon process and is therefore a nonlinear optical effect.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
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.
Author: Christopher Shane Mullin
Publisher:
ISBN:
Category :
Languages : en
Pages : 270
Get Book Here
Book Description
Author: Jar-Mo Chen
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Get Book Here
Book Description
Optical Harmonic Generation is used to detect submonolayers of atoms on solid surfaces. It is shown that nonlinear optical method is much more sensitive than linear reflectance to the surface atoms. A nonlinear optical mixing spectroscopy should be able to detect most of the low lying excitations of a monolayer of atoms adsorbed on solid surfaces. CS of O2 coadsorption on metal and semiconductor surfaces has been studied in detail using LEED, Work function photoemission and Auger spectroscopy. (Author).
Author: Marla Beth Feller
Publisher:
ISBN:
Category :
Languages : en
Pages : 344
Get Book Here
Book Description
Author: Uri Eisner
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
