Nuclear spin symmetry conservation studied by cavity ring-down spectroscopy of ammonia in a seeded supersonic jet from a pulsed slit nozzle
- Conference Paper
We report high-resolution cw laser spectra of the symmetric stretching fundamental in ammonia (Formula presented.) NH (Formula presented.) measured with a cavity ring-down setup for mid-IR transitions (around (Formula presented.)). In a supersonic jet expansion ((Formula presented.) seeded in Ar), we have obtained rotational temperatures below (Formula presented.). For the gas expansion, a pulsed slit nozzle with (Formula presented.) length and 70 µm width has been used. The measured relative line intensities demonstrate that the A and E nuclear spin symmetry isomers do not interconvert in the supersonic jet expansion under these conditions (nuclear spin symmetry conservation). The lateral velocity of the gas expansion has been probed by a Doppler profile measurement, showing a preference for an expansion with an angular distribution following Lambert's cosine law perpendicular to the slit direction and an approximate molecular velocity of about (Formula presented.). The experimental setup is described in detail, also in view of high-resolution spectroscopy of chiral molecules as candidates to measure the parity violating energy difference between enantiomers with a barrier to interconversion around (Formula presented.). © 2020 Informa UK Limited, trading as Taylor & Francis Group. Show more
Journal / seriesMolecular Physics
Pages / Article No.
PublisherTaylor & Francis
SubjectNuclear spin symmetry; Supersonic jet expansion; Cavity ring-down absorption spectroscopy; NH3; Mid-IR high-resolution laser spectroscopy
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