Population diagram of NaCl. A linear fit to the data using all the NaCl transitions detected across all vibrational levels from υ = 0 to υ = 3 indicates a vibrational temperature of T_vib ~ 1125 K (dotted line). The slope of the dashed line, consistent with the observed ln(N_u/g_u) vs. Eu values for the only two NaCl υ = 0 transitions observed, corresponds to T_rot ~ 450 K. The values for the total number of NaCl molecules and column density in the ground vibrational level are indicated, as well as the corresponding values after multiplying the former by the vibrational partition function to account for the NaCl distribution across multiple vibrational levels.