Charge exchange cross section

Charge exchange cross sections depend on a high inverse power of velocity (Bohr, 1948) thus, at high speeds, they are insignificant. At low speeds, however,... 

Note that the charge-exchange cross sections given here are rather approximate. In some special cases, better approximations may be available however, modifications of Bohr s formulas were considered adequate for use over a large range of particle charge and energy. 

From the probability for charge exchange, the charge exchange cross section can be obtained from... 

Figure 13 Charge exchange cross sections due to and (upper left panel), He (lower left panel), He (lower right panel), and He° (upper right panel) impact on water vapor. The curves are fitted to experimental data [199,211-215] by various model functions and extrapolated where data are lacking.

This formula, obtained by Sena [17], correctly describes the dependence of the resonance charge exchange cross-section on the velocity of the colliding... 

The charge exchange cross-section is determined by large impact parameters. This is why, in the course of the calculation of the integral in eqn. (13), it is possible to use the approximation of rectilinear trajectories. Taking into account also the exponential dependence of AW on the interatomic distance, Ml exp( - yR), we have... 

These formulae, obtained by Firsov [18], are widely used to calculate the resonance charge exchange cross-sections [19]. A typical example, demon-... 

The distribution of product states of charge exchange of ions with incident energy W0 is described by dcrL(VT0)/dVT, where W is the energy of the Rydberg electron in the neutral product atom and Ol(Wo) is the total electron loss cross section. As in Eq. (3.3), we can write the charge exchange cross section for the population of a specific n state as... 

Table 3.2. Values of the charge exchange cross section for protons on several vapor targets.

In Fig. 13.9 we show the relative charge exchange cross sections measured for Na+ ions impinging upon Na atoms initially in the 29s and 28d states, which are nearly degenerate in energy.28 For v/ve > 0.8 the two cross sections coincide, but for smaller v the 28d cross section falls below the 29s cross section, except at the lowest velocity. Also shown are the classically scaled cross sections for H+-H Is... 

Omidvar, K. (1975). Asymptotic form of the charge-exchange cross section in three-body rearrangement collisions. Phys. Rev. A 12 911-926. 

Normally the Unit has two to four CRPs active at any time. A normal CRP spans a three year interval, but it is possible to extend this in some circumstances to an additional one or two years. Topics of current CRPs include tritium inventory in fusion reactors, atomic and molecular data for fusion plasma diagnostics, and data for molecular processes in edge plasmas. Tables 15.3-15.5 identify the participants of the current CRPs. Recently completed CRPs include the topics of charge exchange cross-section data for fusion plasma studies, radiated power, and plasma-interaction data for mixed materials, with results now available in the APID series [1-3]. 

Comparing this with the data in Table 1, the real situation is found to be between the cases " a and " c of Hund coupling, but case (6) docs not correspond exactly to any one of the Hund cases. Now we evaluate the exchange ion-atom interaction potential A(i ) on the basis of the formula for the resonant charge exchange cross section (Te,r ill the case of the transition of s—electron [4, 14, 15]... 

Equations 6.100 and 6.102 with ts = te = 1, t = / have been solved for real air in Ref. 16 and in Refs. 51-55, with the latter references utilizing the concept of total properties kT, cpT, Prr. The air properties of Ref. 56 were employed in all the studies except that of Ref. 55, which employed properties evaluated in Refs. 57 and 58, where careful consideration was given to the effect of dominant resonant charge exchange cross sections in establishing the thermal conductivity of ionized nitrogen. 

Fig. 13 shows charge exchange cross sections based on available experimental data for and h (upper left) [211,212], He " (lower left) [199], He" (lower right) [213,214], and He (upper right) [214,215]. There is a probability of two-electron transfer for helium atom, such as (T20 and (7o2- Total cross sections for electron capture crio for and electron loss analytical functions developed by Miller and Green [202]. Cross sections for He ions were least-square fitted by a simple polynomial function similar to Eq. (14). Smooth extrapolation was carried out where the experimental... 

Clearly, the technique has considerable potential and one must hope for its active deployment in the future. To date, the most complicated neutral reactant used has been a diatomic molecule and it may prove difficult to produce sufficiently intense beams of polyatomic neutral reactants by charge exchange rather little is known about the necessary charge-exchange cross sections at high energy. Study of such processes will be necessary, also, to define the internal energy state of the neutral reactant. 

B.J. Nichols and F.C. Witteborn, Measurements of Resonant Charge Exchange Cross Sections in Nitrogen and Argon between 0.5 and 17 eV, NASA Technical Note NASA TN D-3265 (February 1966). 

Et is the ion kinetic energy, A and B are constants) also holds for the variation in the charge exchange cross section with the kinetic energy of polyatomic particles. 

Figure 2. Charge exchange cross sections for the reaction F (Ne,F)Ne state, Q + D states, -, D state, 0.

Barnett CF, Reynolds HK (1958) Charge exchange cross sections of hydrogen particles in gases at high energies. Phys Rev 109 355. doi 10.1103/PhysRev.l09.355... 

---