Abstract
The Rayleigh scattering cross section is measured with a short-duration pulse of laser light in different gases. It depends on the pulse duration, involving a time constant , following the expression , where and are the experimental and the theoretical cross sections and is the classical time constant corresponding to the dipole damping. The time constant was determined with a ruby laser whose pulse half-width was varied between 6 and 200 nsec. Using a tunable dye laser and its nitrogen laser pump, the authors have found that is proportional to (square of the wavelength). The variation of for gases of different molecular sizes shows that is proportional to their diameter . The angular distribution of the scattered light has been determined and found to be favored in the forward direction. The constant is proportional to (where is the scattering angle), i.e., to the momentum transfer. By analogy with a corpuscular collision, dimensional considerations lead to the formula ( is the Compton wavelength), which well describes the experimental results.
- Received 16 June 1978
DOI:https://doi.org/10.1103/PhysRevA.19.2260
©1979 American Physical Society