Inelastic collisions collision number

Figure 53. Newton diagram for He (2 S) + Ne at 66 meV. Largest partial circle is locus of He velocities from elastic collisions smaller numbered ones represent inelastic production of Ne in various final states. Numbers n correspond to subscripts 3s for states of neon (Paschen notation). Angular rays correspond to positions of maxima or shoulders in angular distribution of Fig. 50.

Activation by inelastic collisions is also called thermal activation. After a large number of collisions, a distribution over internal (rotational and vibrational) states will be established as given by the Boltzmann distribution at the given temperature. 

The reader may be surprised not to And a Reynolds number defined speciflcally for the disperse phase. This is because the disperse-phase viscosity is well defined only for Knp 1 (i.e. the collision-dominated or hydrodynamic regime). In this limit, Vp oc oc Knp/Map so that the disperse-phase Reynolds number would be proportional to Map/Krip when Map < 1. However, in many gas-particle flows the disperse-phase Knudsen number will not be small, even for ap 0.1, because the granular temperature (and hence the collision frequency) will be strongly reduced by drag and inelastic collisions. In comparison, molecular gases at standard temperature and pressure have KUp 1 even though the volume fraction occupied by the molecules is on the order of 0.001. This fact can be... 

Due to their lower mass the electrons gain energy far more rapidly and then undergo inelastic collisions. At each inelastic collision the number of electrons increases by a factor of 2. If the average number of collisions is n the amplification factor is 2" an avalanche initiated by one electron thus consists of 2" final ion pairs. The output pulse heights are proportional to the incident photon energy. 

It is relevant to note that studies of rotational relaxation in the collisions of electronically excited diatomic molecules and other atoms or molecules also indicate the absence of any strong constraints to the change in rotational quantum number. The most extensive data are for colhsions of B I2 and other atoms and molecules, from the work of Steinfeld and collaborators. For a given collision partner, say He, the rotational energy distributions generated by vibrationally inelastic collisions are... 

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