Ion beam spectroscopy

Another motivation for considering molecular systems without assuming the BO approximation stems from the realization that in order to reach spectroscopic accuracy in quantum-mechanical calculations (i.e., error less than 1 microhartree), one needs to account for the coupling between motions of electrons and nuclei and, in some cases, also for the relativistic effects. Modern experimental techniques, such as gas-phase ion-beam spectroscopy, reach... 

Reflective boundary/interface — This term originates from the optical, high-vacuum electron- or ion-beam spectroscopies to indicate that the interface between two media reflects the light or particle beam falling on the interface from one of the media, i.e., sends it back to the same medium, in a specular (like a mirror) or diffuse (scattering) way. The same term is also used in diffusion (or diffusion-migration or convective diffusion (-> diffusion)) problems for species inside a solution or a solid phase. In this context it is a synonym of blocking boundary/interface. 

In order to obtain conclusive results one normally focuses on a single transition and detects the emitted fluorescence photons bearing the fine structure information. This is achievable by dye lasers or tunable laser diodes. In some setups the light travels collinearly to fast atomic beams which has some advantages with respect to spectral resolution [44]. The technique of fast ion beam spectroscopy has been applied to numerous measurements on rare earth ions, e.g. [45-49]). Some more recent high-resolution optical hfs measurements include Ta [50], [51] and the noble gas Xe [52] illustrate these advanced... 

Figure 11. Arrangement for collinear laser-rf ion beam spectroscopy after Ref. 70.

Optical double resonance. Assumed. Level-crossing spectroscopy. Optical double resonance. Optical pumping. Assumed. Ion beam spectroscopy. ... 

Proc. Int. Conf. on Fast Ion Beam Spectroscopy, Proc. Colloque No. 1. J. Physique 40 (1978)... 

Principles and Characteristics Ion beam spectroscopy for polymer surface analysis comprises two general classes of experiments. One class uses a primary ion beam to generate secondary ions, which are then mass analysed. This technique, secondary ion mass spectrometry, has evolved into dynamic and static SIMS. Only the latter technique finds frequent application in polymer/additive analysis cfr. Chp. 4.2.1). The second class of ion beam spectroscopy measures the energy loss of a primary ion scattered from a surface. 

For all their useful properties, lasers are known to suffer from drastic limitations in power and/or wavelength range. A a result, their introduction in fast atomic ion beam spectroscopy has often been considered to result in a considerable reduction... 

ISS Ion scattering spectroscopy [153, 154] Inelastic backscattering of ions (-1 keV ion beam) Surface composition... 

Moseley J and Durup J 1981 Fast ion beam photofragment spectroscopy Annual Review of Physical Chemistry ed B S Rabinovitch, J M Schurr and H L Strauss (Palo Alto, CA Annual Reviews)... 

SIMS Secondary Ion mass spectroscopy A beam of low-energy Ions Impinges on a surface, penetrates the sample and loses energy In a series of Inelastic collisions with the target atoms leading to emission of secondary Ions. Surface composition, reaction mechanism, depth profiles... 

As in Auger spectroscopy, SIMS can be used to make concentration depth profiles and, by rastering the ion beam over the surface, to make chemical maps of certain elements. More recently, SIMS has become very popular in the characterization of polymer surfaces [14,15 and 16]. 

Auger electron spectroscopy (AES) is a technique used to identify the elemental composition, and in many cases, the chemical bonding of the atoms in the surface region of solid samples. It can be combined with ion-beam sputtering to remove material from the surface and to continue to monitor the composition and chemistry of the remaining surface as this surface moves into the sample. It uses an electron beam as a probe of the sample surface and its output is the energy distribution of the secondary electrons released by the probe beam from the sample, although only the Ai er electron component of the secondaries is used in the analysis. 

Within the last 5—10 years PIXE, using protons and helium ions, has matured into a well-developed analysis technique with a variety of modes of operation. PIXE can provide quantitative, nondestructive, and fast analysis of essentially all elements. It is an ideal complement to other techniques (e.g., Rutherford backscattering) that are based on the spectroscopy of particles emitted during the interaction of MeV ion beams with the surface regions of materials, because... 

In other articles in this section, a method of analysis is described called Secondary Ion Mass Spectrometry (SIMS), in which material is sputtered from a surface using an ion beam and the minor components that are ejected as positive or negative ions are analyzed by a mass spectrometer. Over the past few years, methods that post-ion-ize the major neutral components ejected from surfaces under ion-beam or laser bombardment have been introduced because of the improved quantitative aspects obtainable by analyzing the major ejected channel. These techniques include SALI, Sputter-Initiated Resonance Ionization Spectroscopy (SIRIS), and Sputtered Neutral Mass Spectrometry (SNMS) or electron-gas post-ionization. Post-ionization techniques for surface analysis have received widespread interest because of their increased sensitivity, compared to more traditional surface analysis techniques, such as X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES), and their more reliable quantitation, compared to SIMS. 

Neutron reflectivity provides a depth resolution of 1 nm and fills an important gap in the resolution between X-ray photoelectron spectroscopy and ion-beam techniques. In this regard, neutron reflectivity promises to play a decisive role in the investigation of solid materials. Equally important is the fact that reflectivity meas-... 

Elastic Recoil Detection Analysis Glow discharge mass spectrometry Glow discharge optical emission spectroscopy Ion (excited) Auger electron spectroscopy Ion beam spectrochemical analysis... 

While electron or ion beam techniques can only be applied under ultra-high vacuum, optical techniques have no specific requirements concerning sample environment and are generally easier to use. The surface information which can be obtained is, however, quite different and mostly does not contain direct chemical information. While with infra-red attenuated total reflection spectroscopy (IR-ATR) a deep surface area with a typical depth of some micrometers is investigated, other techniques like phase-measurement interference microscopy (PMIM) have, due to interference effects, a much better surface sensitivity. PMIM is a very quick technique for surface roughness and homogeneity inspection with subnanometer resolution. 

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