Generalized Landauer equation: absorption-controlled diffusion processes.
The exact expression of the one-dimensional Boltzmann multiple-scattering coefficients, for the passage of particles through a slab of a given material, is obtained in terms of the single-scattering cross section of the material, including absorption. The remarkable feature of the result is that for multiple scattering in a metal, free from absorption, one recovers the well-known Landauer result for conduction electrons. In the case of particles, such as neutrons, moving through a weak absorbing media, Landuer's formula is modified due to the absorption cross section. For photons, in a strong absorbing media, one recovers the Lambert-Beer equation. In this latter case one may therefore speak of absorption-controlled diffusive processes.
Godoy
S
S
Facultad de Ciencias, Universidad Nacional Autónoma de México, México 04510 Distrito Federal, Mexico. sgs@hp.fciencias.unam.mx
García-Colín
L S
LS
Micenmacher
V
V