Published online by Cambridge University Press: 03 August 2017
We compare infrared hydrogen lines observed with ATMOS with computations for two models of the solar atmosphere, one without and one with a chromosphere. The weaker H I lines are formed in the photosphere. Proper evaluation of Stark broadening is required to reproduce their profiles; the heavy ion contribution is most important. The cores of the stronger lines are sensitive to the structure of the chromosphere, but detailed NLTE modeling is needed for diagnostic applications.