Detection of NH3Molecules in the Interstellar Medium by Their Microwave Emission

1968/12/16 by Alvin Cheung, D. M. Rank, C. H. Townes +2 · 3 citations
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Spectroscopy and Laser Applications #Atmospheric Ozone and Climate #Astrophysics and Star Formation Studies

paper · doi:10.1103/physrevlett.21.1701

openalex publication_date 1968/12/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/10

Abstract

Ammonia has been found in the direction of the galactic center by detection of its J=1, K=1 inversion transition. The region of emission closely corresponds to the position, velocity, and size of strong OH absorption. Collisional and radiative excitation mechanisms are discussed. The column density of NH₃ and the kinetic temperature of the interstellar gas cloud are estimated to be 2\ifmmode×\else\texttimes\fi10¹⁶/cm² and 23\ifmmode^∘\else\textdegree\fiK, respectively.

Cited by

• Evidence for Extraterrestrial Amino-acids and Hydrocarbons in the Murchison Meteorite
• Ammonia [wikipedia]
• Rotational spectroscopy [wikipedia]