FREE-FREE TRANSITIONS IN COLLISIONS BETWEEN SLOW-ELECTRONS AND NEUTRAL OXYGEN-ATOMS

The absorption coefficients for the free-free transitions in collisions between slow electrons and neutral oxygen atoms have been calculated for wavelengths in the range of 1 to 30 μm and temperatures between 5000 and 50 000 K. The wave functions of the unbound electron are the solutions of a one-electron Schrödinger-like continuum equation that includes the Coulomb, exchange, and polarization interactions with the oxygen atom. The polarization potential is determined by a first-principles calculation based on the method of polarized orbitals. Our absorption coefficients are in good agreement with those of John and Williams [J. Quant. Spectrosc. Radiat. Transfer 17, 169 (1977)], but are much smaller than the experimental data of Taylor and Caledonia [J. Quant. Spectrosc. Radiat. Transfer 9, 681 (1969)] and of Kung and Chang [J. Quant. Spectrosc. Radiat. Transfer 16, 579 (1976)]. © 1995 The American Physical Society.