| Presenter: | Véronique Bommier |
| Affiliation: | LERMA, Paris Observatory |
| Title: | Atomic and molecular depolarizing collision rates |
| Authors: | V. Bommier |
| Form: | invited |
| Abstract: | The depolarization by collisions is a non-negligible ingredient of the formation of the line polarization, in particular in the second solar spectrum, which is the spectrum of the linear polarization formed by scattering and observed near the solar limb. In the case of the widely studied Sr~{\sc{i}}~460.7 nm line, the depolarization due to collisions with the surrounding hydrogen atoms is as large as the magnetic depolarization due to the Hanle effect. In the solar photosphere and chromosphere, the depolarizing collisions are due to hydrogen atoms. A review will be given about the theoretical work on the depolarizing rates computation for atoms. For molecules a comparable work will probably not be available in the near future. The case of MgH, where the second solar spectrum has played the role of a laboratory and has permitted the experimental determination of depolarizing collision rates in the excited level of MgH (collisions MgH + H), will be presented and discussed, several different values being found in the literature. |
| Session: | 5. Molecular polarization and collisional depolarization |
| Presentation date: | Wednesday 19th September |
| Presentation time: | 09:30:00 |