MOLLId: Software for Automatic Identification of Molecules and Its Application to the Spectra of Protostars from the Region RCW 120

In this work, we present the program MOLLId (MOLecular Line Identification) for automated molecular line approximation with a Gaussian profile. Molecular identification was performed using multi-level comparison of the lines’ center frequencies and rest frequencies from the spectroscopic database. The program was tested in the identification of molecular lines in observed spectra of young stellar objects RCW 120 YSO S1 and RCW 120 YSO S2 located near the border of the RCW 120 PDR. In the spectra of the RCW 120 YSO S1 source, 100 lines of 41 molecules were identified over the level of 4–6 $$\sigma$$ . In the spectra of the RCW 120 YSO S2 source, 407 lines of 79 molecules were identified over the 3–5 $$\sigma$$ level. Using the Intel Core i7-12700K CPU, identification time is equal to 6 and 8 minutes per spectral range for the YSOs S1 and S2, respectively. From the analysis of CH $${}_{3}$$ OH, CH $${}_{3}$$ CN, CH $${}_{3}$$ CCH molecules identified in RCW 120 YSO S2, we found a two-component structure and estimated the physical parameters in the LTE approximation for each of the components.