# Grid/NLTE
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Version 8, 5 May 2026

Non-LTE departure coefficients are provided for the element Ag, calculated
across a grid of 3756 1D MARCS model stellar atmospheres (Gustafsson et al.
2018, A&A, 486, 951) spanning 3000<T_{eff}/K<8000, -0.5<log(g/cm s^{-2})<5.5,
and -5<[Fe/H]<+1.  Abundances are relative to the solar chemical composition of
Grevesse et al. (2007, Space Sci. Rev, 130, 105). Please refer to Caliskan et
al., ``Ag I model atom and the 3D non-LTE solar silver abundance'', submitted to
A&A, and references therein, for further details on the calculations.

This version includes background Thomson and Rayleigh scattering.  Background
line opacities are treated in pure absorption.

The data are available in ASCII files, and also in formats compatible with the
spectrum synthesis codes Spectroscopy Made Easy (SME; Piskunov et al. 2017, A&A,
597, A16) and PySME (Wehrhahn et al. 2023, A&A, 671, A171).  It is important
that the user checks that the level labels in their linelists are consistent
with the level labels in the non-LTE grids.  

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Data files
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    atmos_Ag.txt: contains the MARCS atmosphere index (starting at 1), and the
    corresponding atmosphere parameters Teff/K, log(g/cm s^-2), and [Fe/H].
    [format='(i4,x,i4,x,f5.2,x,f5.2,x,i2,x,e10.3)']
    
    label_Ag.txt: contains the level index (starting at 1), and the
    corresponding species, electron configuration, spectroscopic term, total
    angular momentum quantum number J, and energy with respect to the ground
    state of that ionisation stage in eV.
    [format='(i4,x,a4,x,a30,x,a10,x,f5.1,x,f20.9)']
    
    Other .txt files: contain the MARCS atmosphere index (starting at 1), the
    depth index in that MARCS atmosphere (where 1 is the top and 56 is the
    bottom), [X/Fe], the level index (starting at 1), and the departure
    coefficient b = n_{NLTE}/n_{LTE}.  [format='(i4,x,i2,x,f5.2,x,i4,x,e10.3)']
    
    Files ending _pysme.grd: contains the grid in a format that is compatible
    with PySME.  Please check that the level labels in the adopted linelists are
    consistent with the level labels in the non-LTE grids.  PySME has an option
    where if it fails to find the desired level from the linelist in these
    grids, it takes the level that is closest in energy, without extrapolation.
    These grids should be used with the marcs2012 or marcs2014 families of model
    atmospheres.
    
    Files ending _idlsme.grd: contains the grid in a format that is compatible
    with IDL-SME.  It is extremely important to check that the level labels in
    the adopted linelists are consistent with the level labels in the non-LTE
    grids.  If IDL-SME fails to find the desired level from the linelist in
    these grids, LTE populations will be adopted.  These grids should be used
    with the marcs2012 or marcs2014 families of model atmospheres.
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