Upper panels: comparison between the atomic partition functions (Q) calculated in this work with data from NIST (blue curves) and the ones provided by Irwin (1987; red curves) and by Lawler & Sneden (MOOG data, version from July 2014; see also Sneden 1973 and updates; green dots). Partition functions from Irwin (1987) are extended to temperatures below 1000 K using constant extrapolation (red dashed curves). Data from Lawler & Sneden are interpolated in between the sampled temperature points using cubic splines in log Q. Lower panels: relative differences between the partition function calculations by the other authors and ours.