Millimeter-wave observations of the NH3–D2 and ND3–H2 van der Waals complexes

The rotational spectra of the NH 3 –D 2 and ND 3 –H 2 van der Waals complexes have been observed in a supersonic molecular jet for the first time. The OROTRON intracavity spectrometer was used to detect pure rotational transitions in the frequency range from 75 to 120 GHz. The search of the spectral lines was based on the initial observation of the main isotopic species of the NH3−H2. The measured transition frequencies including hyperfine splitting were analyzed in order to determine the energy levels, molecular parameters and structure of the ortho ND 3 − ortho H 2 and ortho NH 3 − para D 2 complexes.