Cross section for collision

Tusa J., Sulkes M., Rice S. A. Very low energy cross sections for collision-induced rotational relaxation of I2 seeded in a supersonic free jet, Proc. Natl. Acad. Sci. USA 77, 2367-9 (1980). 

Jphe polarization theory predicts a cross-section for collisions ... 

Figure 11. Ratio of experimental values of formation cross-section of CH0 + to calculated Langevin cross-section for collision of CH + with CH as a function of average ion kinetic energy...

Decreasing particle size means increased effort required to remove it. This rule arises from the smaller interaction cross sections for collision and momentum transfer. Furthermore, the electrostatic forces are stronger for smaller particles, and they diminish in proportion to 1/r as opposed to 1/r. Both of these factors lead to redeposition being a major source of small particles. Since mechanical action requires increasing amounts of work, chemical dissolution is more effective at removing small particles than is mechanical action. 

The total cross section for collision with a fast particle is never greater than twice the geometrical cross-sectional area of the nucleus and therefore, fast particle cross-sections are rarely much larger than 10- 4 cm (radii of the heaviest nuclei are about 10- cjjij Hence a cross-section of 10-24 considered as... 

Figure 12 Calculated Penning ionization cross sections for collisions (--------) He(2 P)-Ar, (-----),...

Figure 8.2 The elastic scattering cross section for collisions of O2 molecules in the lowest energy Zeeman state Mg = = —1) as a function of the magnetic field. The collision energy is 10 ...

The energy dependences of the cross sections for collision-induced dissociation (CID) reactions of the form... 

Kover, A., Laricchia, G. and Charlton, M. (1994). Doubly differential cross sections for collisions of 100 eV positrons and electrons with argon atoms. 

Double-differential cross sections for collisions of positrons with argon atoms. J. Phys. B At. Mol. Opt. Phys. 30 L507-L512. 

For a spherical particle, the effective cross section for collision, a, is... 

Frommhold L, Hong-Hong K, Proffitt MH (1978) Absolute cross sections for collision-induced depolarized scattering of light in krypton and xenon. Mol Phys 35 665-700... 

Busalla A, Blum K, Thompson DG (1999) Differential cross section for collisions between electrons and oriented chiral molecules. Phys Rev Lett 83 1562... 

L. Frommhold, K. H. Hong, and M. H. Proffitt. Absolute cross sections for collision induced scattering of light by binary paris of argon atoms. Molec. Phys., 35 665-619 (1978). 

Figure 9 Relative cross sections for collisions assisted by zero photons (o and solid line), one photon ( and dashed line), two photons (A and long-short dashed line), three photons ( , dot-dashed line). The lines are calculated from Eq. (14).

There has been a predecessor to the Bennewitz-experiment Berkling et al. (1962) have measured the total cross section for collisions between oriented 2P3/2 Ga atoms with noble gas molecules. This experiment was never taken up again although there is a whole group of atoms with anisotropic electronic structure which can be likewise oriented. The information which can be obtained from scattering experiments with oriented atoms is essentially the same as with oriented molecules. 

Perturbations affect the rate of absorption and emission of radiation in a fully understood and exactly calculable manner. They also affect the rates of chemical and collisional population/depopulation processes, but in a less easily estimated way. Perturbation effects on steady-state populations can be very large and level-specific. Although collision-induced transitions and chemical reactions are not governed by rigorous selection rules as are electric dipole transitions and perturbation interactions, some useful propensity rules have been suggested theoretically and confirmed experimentally. Gelbart and Freed (1973) suggested that the cross sections for collision-induced transitions between two different electronic states, E and E, are... 

Studies of collision-induced mode-to-mode energy transfer in the ground electronic states of several small polyatomics reveal two qualitative features of the process. First, the energy-transfer cross-sections are, with only a few exceptions, small compared with the cross-section for collision. Second, there are strong propensity rules governing the pathways of mode-to-mode transfer so that not all levels within the range defined by the distribution of collision energies are equally accessible from the initial level. 

The cross-section for collision-induced rotational energy transfer is very large, of the order of magnitude of the hard sphere cross-section or larger. 

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