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Updated: Oct 29, 2025

Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Rotational spectroscopic study and astronomical search for propiolamide in Sgr B2(N)
E R Alonso1,2, L Kolesniková3, A Belloche4
1Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, Spain.
Researchers studied propiolamide, an amide counterpart to cyanoacetylene, to aid its detection in space. Despite extensive laboratory measurements, propiolamide was not detected in the Sgr B2 star-forming region, suggesting low interstellar abundance.
Area of Science:
- Astrochemistry
- Molecular Spectroscopy
- Interstellar Medium
Background:
- Amides and their corresponding nitriles are found in the interstellar medium (ISM).
- Cyanoacetylene (HCCCN) is an abundant interstellar nitrile, but its amide counterpart, propiolamide (HCCC(O)NH2), has not been detected.
- Understanding the abundance of propiolamide is crucial for completing the picture of interstellar amide-nitrile chemistry.
Purpose of the Study:
- To conduct a comprehensive rotational study of propiolamide across a wide frequency range (6 GHz to 440 GHz).
- To provide accurate spectroscopic parameters for propiolamide to facilitate its astronomical detection.
- To investigate the abundance of propiolamide in the star-forming region Sgr B2(N).
Main Methods:
- Utilized time-domain Fourier transform microwave (FTMW) spectroscopy for high-resolution ground-state measurements (6-18 GHz).
- Employed frequency-domain millimeter and submillimeter wave spectroscopy (75-440 GHz) for ground and excited vibrational states.
- Analyzed data using an effective semi-rigid rotor Hamiltonian, including 14N nuclear quadrupole coupling interactions.
- Searched for propiolamide in the ReMoCA spectral line survey data from Sgr B2(N).
Main Results:
- Identified and measured over 5500 distinct laboratory frequency lines of propiolamide.
- Obtained accurate spectroscopic parameters for the ground and three low-lying excited vibrational states.
- Did not detect propiolamide in the Sgr B2(N1S) and Sgr B2(N2) hot cores.
- Established upper limits for propiolamide abundance, finding it at least 50 and 13 times less abundant than acetamide in the studied regions.
Conclusions:
- The non-detection and derived upper limits suggest propiolamide is a minor species in the studied interstellar regions.
- The abundance ratios of propiolamide to acetamide are consistent with predictions from astrochemical models.
- The comprehensive spectroscopic data will enable future, more sensitive astronomical searches for propiolamide.
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