Spectra obtained toward the central position of Cha-MMS1 in the optically thick CS 2−1, HCO⁺ 3−2, HCO⁺ 1−0, and HNC 1−0 transitions and the low optical depth C³⁴S 2−1, H¹³CO⁺ 1−0, H¹³CO⁺ 3−2, H¹³CO⁺ 4−3, HC¹⁸O⁺ 1−0, and HN¹³C 1−0 transitions. The dashed line corresponds to the systemic velocity derived from a seven-component hyperfine fit to the N₂H⁺ 1−0 multiplet (4.3 km s^-1). It is corrected to 4.4 km s^-1 for the APEX transitions HCO⁺ 3−2, H¹³CO⁺ 3−2, and H¹³CO⁺ 4−3 (see Sect. 3.2.1).