Na D 3s − 3p doublet line core with resolved fine structure broadened by collision with H₂. This is a composite of spectra taken with cell temperatures from 470 K to 873 K joined overlapped and scaled to match. The highest temperature was used to increase the Na density and bring out the wing, and the lowest temperature was used to avoid saturation in the line center. The representative density is n_H2 = 1.0 × 10¹⁹ cm^-3. The spectrum is shown relative to the mean 3s − 3p transition energy.