3 mm spectroscopic observations of massive star-forming regions with IRAM 30 m.

This article presents high-sensitivity broad-band spectroscopic observations of 50 Galactic massive star-forming regions conducted with the IRAM 30 m millimeter telescope, covering frequencies from 105.8 to 113.6 GHz. A total of 27 molecular species were identified, including 16 complex organic molecules (COMs, defined as molecules with six or more atoms), with detailed parameters such as peak temperature, integrated intensity, and line width reported. The study finds strong positive correlations in line widths and column densities among chemically related molecules, suggesting they originate from similar gaseous environments within star-forming regions. Additionally, the protonated carbon dioxide ion HOCO⁺ was detected in several sources, providing insights into interstellar chemistry. The dataset offers a valuable resource for further astrochemical studies on the evolution and formation pathways of molecules in massive star-forming cores.