Monoenergetic beam

LEIS Low-energy ion scattering [155-157] A monoenergetic beam of rare-gas ions is scattered elastically by surface atoms Surface composition... 

In a very simple fonn of electron spectroscopy, known as electron transmission spectroscopy, the attenuation of an essentially monoenergetic beam of electrons is measured after passage tlnough a sample. If the target is very thin or of such low density that most electrons pass tlnough unscattered, the attenuation is small and the... 

A unifonn monoenergetic beam of test or projectile particles A with nnmber density and velocity is incident on a single field or target particle B of velocity Vg. The direction of the relative velocity m = v -Vg is along the Z-axis of a Cartesian TTZ frame of reference. The incident current (or intensity) is then = A v, which is tire number of test particles crossing unit area nonnal to the beam in unit time. The differential cross section for scattering of the test particles into unit solid angle dO = d(cos vji) d( ) abont the direction ( )) of the final relative motion is... 

In order to estimate the photoelectron yield from a chemisorbed layer we follow the approach of Henke (S), applied by Madey et al. (9), and modified by Carley and Roberts (10). A monoenergetic beam of x rays strike a surface at an angle 0 to the surface normal the photoelectrons, assumed to be generated in a layer of depth X and thickness dx, escape from the sample to a detector positioned at an angle with respect to the surface normal. The differential probability dP of absorption of x rays at depth X within the thickness dx is... 

ESCA involves the measurement of binding energies of electrons ejected by interactions of a molecule with a monoenergetic beam of soft X-rays. For a variety of reasons the most commonly employed X-ray sources are Al and MgKol>2 with corresponding photon energies of 1486.6 eV and 1253.7 eV respectively. In principle all electrons, from the core to the valence levels can be studied and in this respect the technique differs from UV photoelectron spectroscopy (UPS) in which only the lower energy valence levels can be studied. The basic processes involved in ESCA are shown in Fig. 1. 

Fig. 2.5. Classical and quantum calculation of the scattering of H2 by Hg in the idealization where both systems are considered to have zero angular momentum. In actuality, the undulations will be partly washed out by effects associated with the rotation of the molecule, the spin of the protons, and the energy spread in the monoenergetic beam after [30],...

Monoenergetic beams of atoms are scattered from ordered surfaces and detected as a function of scattering angle. This gives structural information on the outermost layer of the surface. Atom diffraction is extremely sensitive to surface ordering and defects. 

A monoenergetic beam of electrons is used to excite atoms in the near surface region. As the beam energy is swept, variations in the sample emission current occur as the beam energy sweeps over the energy of an Auger transition in the sample. Also known as APAES. 

Positrons and positronium (Ps), the bound state of a positron with an electron, are highly sensitive to open volume in a material. Their sensitivity ranges from monovacancies (positrons) to voids to pores of several 10 nm in cross section (positronium). With a variable energy monoenergetic beam, positrons can be implanted in a sample at a chosen depth (or range of depths for a profile). Dependent on the porosity properties of the sample, positronium may be formed there. When positrons and positronium... 

Mangles SPD, Murphy CD, Najmudin Z et al. (2004) Monoenergetic beams of relativistic electrons from intense laser-plasma interactions. Nature 431 535-538. 

Ion scattering spectroscopy (ISS) was introduced by Smith [25] using noble gas ions and has become a powerful tool for surface analysis. In low-energy ion scattering (LEIS), a monoenergetic beam of low-energy ions in the 0.2-5-keV range is directed... 

For surface structure studies, perhaps the most popular technique has been LEED (373). Elastically diffracted electrons from a monoenergetic beam directed to a single-crystal surface reveal structural properties of the surface that may differ from those of the bulk. Some applications of LEED to electrocatalyst characterization were cited in Section IV (106,148,386). Other, less specific, but valuable surface examination techniques, such as scanning electron microscopy (SEM) and X-ray microprobe analysis, have not been used in electrocatalytic studies. They could provide information on surface changes caused by reaction, some of which may lead to catalyst deactivation (256,257). Since these techniques use an electron beam, they can be coupled with previously discussed methods (e.g. AES or XPS) to obtain a qualitative mapping of the structure and composition of a catalytic surface. 

In applications where a monoenergetic beam is needed, mechanical chopping by means of one slotted wheel is sufficient.45,52 In all time-of-flight methods the velocity resolution Av/v is proportional to the beam velocity typical values for a potassium beam are Av/v = 0 05. ( )1/2, where E is in... 

Helium atom scattering Monoenergetic beam of helium Gas-solid 1996HOF/TOE... 

A uniform monoenergetic beam of test or projectile particles A with number density and velocity is... 

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