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Title: Depolarizing collisions with hydrogen: Neutral and singly ionized alkaline earths

Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkali earths Mg I, Sr I, Ba I, Mg II, Ca II, and Ba II, due to collisions with H°. We compute ab initio potential curves of the atom-H° system and solve the quantum mechanical dynamics. From the scattering amplitudes, we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T ≤ 10,000 K. A comparative analysis of our results and previous calculations in the literature is completed. We discuss the effect of these rates on the formation of scattering polarization patterns of resonant lines of alkali earths in the solar atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.
Authors:
; ;  [1] ; ;  [2] ;  [3]
  1. Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain)
  2. Instituto de Física Fundamental (IFF-CSIC), CSIC, Serrano 123, E-28006 Madrid (Spain)
  3. Departamento de Química Física, Unidad Asociada UAM-CSIC, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, E-28049 Madrid (Spain)
Publication Date:
OSTI Identifier:
22356614
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; COLLISIONS; DATA ANALYSIS; DISTRIBUTION; ELEMENT ABUNDANCE; HYDROGEN; MAGNETIC FIELDS; POLARIZATION; SCATTERING; SCATTERING AMPLITUDES; SOLAR ATMOSPHERE; SUN