MOBILITY OF ELECTRONS IN THE NOBLE GASES
A theoretical study which leads to formulas that relate the cross section for inelastic collisions near the threshold energy to the drift velocity v/sub d/ of electrons in noble gases is made. Derivation of general formulas for v/sub d/ follows a qualitative interpretntion of the main features of the experimental drift-velocity curves. The formulas for v/sub d/ are derived for the case in which the elastic cross section for momentum transfer is given by N/ sub 0/Q/sub m/ (v) - av/sup J-1/. Closedform expressions for v/sub d/ are obtained by integrating only over the distribution function for electrons that have energy less than the excitation energy u/sub 1/. By this procedure, integration over the high-energy (u > u/sub 1/) distribution function is avoided and the use of analytical methods is made possible. A partial correction to this approximation is obtained by extending the low-energy (u < u/sub 1/) distribution function to pass through zero at an energy u/sub 0/ that is greater than u/sub 1/. From the drift-velocity formula and the experimental values of v/sub d/, the cutoff energy u/sub 0/ can, in principle, be evaluated as a function of E/p. The highenergy distribution function is used to derive an expression for the overshoot (u/sub 0/--u/sub 1/) which is shown to be proportional to (E/p)/sup 2/( gamma +2)/ and to depend upon the constants h and gamma when the inelastic- collision cross section has the form Q/sub 1/(u) - h(u--u/sub 1/) gamma . Possible applications of these theoretical results to drift-velocity data for gas mixtures are also briefly discussed. (auth)
- Research Organization:
- Argonne National Lab., Ill.
- NSA Number:
- NSA-18-016668
- OSTI ID:
- 4063017
- Journal Information:
- Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Vol. Vol: 134; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Molecular beam measurements of inelastic cross sections for transitions between defined rotational states (j,m) of CsF in collisions with He, Ne, Ar, Kr, CH/sub 4/, CF/sub 4/, SF/sub 6/, C/sub 2/H/sub 6/, N/sub 2/, CO, CO/sub 2/, N/sub 2/O, CH/sub 3/Cl, CH/sub 3/Br, CF/sub 3/H, and CF/sub 3/Br
ELECTRON VELOCITY DISTRIBUTIONS IN GASES