Optical second harmonic generation (SHG) on the diamond C(111) surface 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 Optical second harmonic generation (SHG) on the diamond C(111) surface PDF full book. Access full book title Optical second harmonic generation (SHG) on the diamond C(111) surface by Manfred Buck. Download full books in PDF and EPUB format.
Author: Manfred Buck
Publisher:
ISBN:
Category :
Languages : de
Pages : 7
Get Book Here
Book Description
Author: Manfred Buck
Publisher:
ISBN:
Category :
Languages : de
Pages : 7
Get Book Here
Book Description
Author: M. Buck
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Get Book Here
Book Description
Author: Pierre-François Brevet
Publisher: EPFL Press
ISBN: 9782880743451
Category : Electrochemistry
Languages : en
Pages : 162
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Second harmonic generation (SHG) and infrared-visible sum frequency generation (SFG) spectroscopies have been shown to be powerful and versatile for studying surfaces with submonolayer sensitivity. They have been used in this work to study bare diamond surfaces and molecular adsorption on them. In particular, infrared-visible SFG as a surface vibrational spectroscopic technique has been employed to identify and monitor in-situ surface bonds and species on the diamond (111) surface. The CH stretch spectra allow us to investigate hydrogen adsorption, desorption, abstraction, and the nature of the hydrogen termination. The C(111) surface dosed with atomic hydrogen was found to be in a monohydride configuration with the hydrogen atoms situated at top-sites. The ratio of the abstraction rate to the adsorption rate was appreciable during atomic hydrogen dosing. Kinetic parameters for thermal desorption of H on C(111) were determined showing a near first-order kinetics. For the fully H-terminated (111) surface, a large (110 cm[sup[minus]1]) anharmonicity and[approximately]19 psec lifetime were measured for the first-excited CH stretch mode. The bare reconstructed C(111)-(2[times] l) surface showed the presence of CC stretch modes which were consistent with the Pandey[pi]-bonded chain structure. When exposed to the methyl radical, the SFG spectra of the C(111) surface showed features suggesting the presence of adsorbed methyl species. After heating to sufficiently high temperatures, they were converted into the monohydride species. Preliminary results on the hydrogen-terminated diamond (100) surface are also presented.
Author: Rodney Peter Chin
Publisher:
ISBN:
Category :
Languages : en
Pages : 316
Get Book Here
Book Description
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: Marla Beth Feller
Publisher:
ISBN:
Category :
Languages : en
Pages : 344
Get Book Here
Book Description
Author: Daniel Alfred Higgins
Publisher:
ISBN:
Category :
Languages : en
Pages : 424
Get Book Here
Book Description
Author: Xiujuan Wang
Publisher:
ISBN:
Category : Harmonics (Electric waves)
Languages : en
Pages : 102
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
Get Book Here
Book Description
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.
