相关论文: Depolarization of MgH Solar Lines by Collisions wi…
This paper is a continuation of a series of studies investigating collisional depolarization of solar molecular lines like those of MgH, CN and C$_2$. It is focused on the case of the solar molecule C$_2$ which exhibits striking scattering…
Neutral and singly ionized states of the Magnesium (Mg) are the origin of several spectral lines that are useful for solar diagnostic purposes. An important element in modeling such solar lines is collisional data of the Mg with different…
Simulations of the generation of the atomic polarization is necessary for interpreting the second solar spectrum. For this purpose, it is important to rigorously determine the effects of the isotropic collisions with neutral hydrogen on the…
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…
Our work is concerned with the case of the solar molecule CN which presents conspicuous profiles of scattering polarization. We start by calculating accurate PES for the singlet and triplet electronic ground states in order to characterize…
Interpretation of solar polarization spectra accounting for partial or complete frequency redistribution requires data on various collisional processes. Data for depolarization and polarization transfer are needed but often missing, while…
Analysis of the Hanle effect in solar molecular lines allows us to obtain empirical information on hidden, mixed-polarity magnetic fields at subresolution scales in the (granular) upflowing regions of the `quiet' solar photosphere. Here we…
The theory of collisional depolarization of spectral lines by atomic hydrogen (Derouich et al. \cite{derouich1}) is extended to $d$ $(l$=2) atomic levels. Depolarization rates, polarization and population transfer rates are calculated and…
Collisional de-excitation rates of partially deuterated molecules are different from the fully hydrogenated species because of lowering of symmetry. We compute the collisional (de)excitation rates of ND2H by ground state para-H2, extending…
Rigorous implementation of the effects of collisions in modeling the formation of the polarized solar lines is of utmost importance in order to realistically analyze the available, highly sensitive solar spectropolarimetric observations.…
Context: The scattering polarization of the infrared (IR) triplet of neutral oxygen (O\,\textsc{i}) near 777\,nm provides a powerful diagnostic of solar atmospheric conditions. However, interpreting such polarization requires a rigorous…
Analysis of solar magnetic fields using observations as well as theoretical interpretations of the scattering polarization is commonly designated as a high priority area of the solar research. The interpretation of the observed polarization…
Results. We consider the problem of isotropic collisions between an alkali atom and neutral hydrogen. We calculate the collisional tensorial components of general p and s-states, characterized by their effective principal quantum number…
The present paper extends the method of Anstee, Barklem and O'Mara (Anstee 1992; Anstee & O'Mara 1991, 1995; Anstee, O'Mara & Ross 1997; Barklem 1998; Barklem & O'Mara 1997; Barklem, O'Mara & Ross 1998), developed during the 1990's for…
This work aims to provide key elements to gain better understanding of the formation of the second solar spectrum of the Sr II $\lambda$4078 line. We show that in a certain range of hydrogen density, the effect of isotropic collisions…
Recently, the production of ultrahigh-density (~10^{19}cm^{-3}) spin-polarized deuterium (SPD) atoms was demonstrated, from the photodissociation of deuterium iodide, but the upper density limit was not determined. Here, we present studies…
The theory of collisional depolarization of spectral lines by atomic hydrogen (Derouich et al. 2003a; Derouich et al. 2003b) is extended to $f$-atomic levels $(l$=3). Depolarization rates, polarization and population transfer rates are…
The spin temperature of neutral hydrogen, which determines the 21 cm optical depth and brightness temperature, is set by the competition between radiative and collisional processes. In the high-redshift intergalactic medium, the dominant…
We calculate the light-induced collisional loss of laser-cooled and trapped magnesium atoms for detunings up to 50 atomic linewidths to the red of the ^1S_0-^1P_1 cooling transition. We evaluate loss rate coefficients due to both radiative…
The physical interpretation of scattering line polarization offers a novel diagnostic window for exploring the thermal and magnetic structure of the quiet regions of the solar atmosphere. Here we evaluate the impact of isotropic collisions…