Charged particles interaction

This book lays emphasis on the fundamental aspects of the chemical consequences of charged particle interactions with matter, particularly in the condensed phase. No details will be given about experimental apparatus or procedure, but results of experiments are discussed in relation to theoretical models. The role of the electron both as a radiation (primary and secondary) and as a reactant has been fully treated. Wherever necessary, physical theories have been discussed in detail with understanding of radiation-chemical experiments in view. 

ICRU Report 55. Secondary Electron Spectra from Charged Particle Interactions, International Commission on Radiation Units and Measurements Bethesda, MD, 1995. 

Following from formula (4.54), the transfer of energy on excitation of molecules has a noticeable probability even in the case where the impact parameter is much greater than their size d. Since the intermolecular spacings in a condensed medium are of order of d, a charged particle interacts with many of its molecules. The polarization of these molecules weakens the field of the particle, which, in its turn, weakens the interaction of the particle with the molecules located far from the track. This results in that the actual ionization losses are smaller than the value we would get by simply summing the losses in collisions with individual molecules given by formula (5.1). This polarization (density) effect was first pointed out by Swann,205 while the principles of calculation of ionization losses in a dense medium were developed by Fermi.206... 

The prompt gamma-rays emitted following neutron or charged particle interactions with the target nuclide may be used as a basis for non-destructive analyses. The important advantage of this technique is that the determination does not depend in any manner on the half-life of a product radionuclide. In fact, using this technique, the product nuclide need not even be radioactive. Many conventional activation determinations are limited in their sensitivities by short half-life product radionuclides, or the fact that the most abundant or highest cross section isotope of the element to be determined leads to a stable product on irradiation. 

Consider a system of charged particles interacting with a pulse of light. The dynamics of the particles and of electric field E(r, t) and magnetic field B(r, t) are determined by combining Maxwell s equations for the fields [1]... 

The vast majority of work on particle-surface electrostatic interactions has neglected any effects due to particle motion. However, both theoretical [31,32] and experimental work [33-35] have been done on the problem of a charged particle interacting with a charged wall in a linear shear flow. In the theoretical treatment, it is assumed that the double layer thickness is small compared to both the particle diameter and the surface-to-particle gap. Hence, changes in the pressure and potential profiles in the gap caused by motion can be written as small perturbations to their equilibrium profiles. In the region outside the small double layers, the fluid velocity v and perturbation pressure dp are governed by Stokes equations... 

Charged particles interact with one another according to Coulomb s law ... 

R. E. Johnson, Energetic Charge-Particle Interaction with Atmosphere Surface (Springer-Verlag, Berlin, 1990). 

In addition to interacting with atomic electrons, charged particles interact with nuclei when passing through matter. When approaching the nucleus the charged particle feels a potential... 

A general description of the problem can be made as follows a point charge Zj is moving parallel to the surface with velocity v along the v-direction at a distance Zq > 0. Henceforth, z is the coordinate of the position vector normal to the surface. The top-most atomic layer is at z = 0 and the solid in the z < Q side. We use capital letters for the coordinates parallel to the surface [r = (R, z)]. When a swift charged particle interacts... 

To examine this system exactly, however, offers a problem in the dynamics of three charged particles interacting according to Coulomb s law (Fig. 5.1), an instance of the famous three-body problem. Even in classical mechanics, to say nothing of wave mechanics, it has not been solved analytically. The first approximation to introduce is suggested by the expectation that the relatively heavy protons will move so much less rapidly than the electron that they will be responding primarily to a cloud of electronic charge. 

Consider a system that can be decomposed into n-electrons and m-nuclei. The total hamiltonian H includes the field mediating the interactions between the charged constituents. Charged particles interact via the four vector potential (0, A), where 0 is the Coulomb potential and A is the transverse electromagnetic potential. This Hamiltonian is obtained as a non-relativistic limit of Dirac s Hamiltonian [10] ... 

An example of (6.41) is two charged particles interacting according to Coulomb s law [see Eq. (3.53)]. With this restriction on V, the Hamiltonian function is... 

The internal temperature is expected to reach a stationary value due to the competition between the (long-range) collisions between charged particles, interaction with black-body radiation, and collisions with residual gas molecules. The cross-section for collisions between a molecular ion and another charged particle (which in the ensembles discussed here can be another molecular ion or a laser-cooled atomic ion) that induce transitions between the rotational or vibrational states has been discussed in Ref. [102]. The transition probability between two (rovibrational) states n and n is modeled by... 

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