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Sub-Doppler slit jet infrared spectroscopy of astrochemically relevant cations: The NH stretching mode in ND3H+
- Source :
- The Journal of Chemical Physics. 149:144303
- Publication Year :
- 2018
- Publisher :
- AIP Publishing, 2018.
-
Abstract
- High-resolution rotationally resolved spectra of the N–H stretch vibrational mode (ν1) of jet-cooled ND3H+ ions are collected and analyzed in a sub-Doppler slit-jet infrared spectrometer. The isotopomeric ammonium ions are generated by proton transfer from H3+ to ND3 in a discharge of an ND3/H2 gas mixture, whereby the slit jet expansion cools the nascent ND3H+ ions into lower rotational states. Rotational assignments are confirmed by four-line combination differences that agree to within the spectrometer precision (9 MHz). Based on precision two-line ground-state combination differences and a symmetric top Hamiltonian, the B, DJ, and DJK rotational constants for the ground vibrational state of ND3H+ are determined with high precision for the first time. Approximate rotational constants for the ν1 excited state are also determined, with a band origin at 3316.8425(19) cm−1 and in remarkable (∼0.1 cm−1) agreement with high level anharmonic theoretical predictions by Guo and co-workers [J. Phys. Chem. A, 120, 2185 (2016)]. Our results allow us to predict several low-J pure rotational transitions of ND3H+, which we hope will support future studies of this important ion in laboratory and astronomical rotational spectroscopy.High-resolution rotationally resolved spectra of the N–H stretch vibrational mode (ν1) of jet-cooled ND3H+ ions are collected and analyzed in a sub-Doppler slit-jet infrared spectrometer. The isotopomeric ammonium ions are generated by proton transfer from H3+ to ND3 in a discharge of an ND3/H2 gas mixture, whereby the slit jet expansion cools the nascent ND3H+ ions into lower rotational states. Rotational assignments are confirmed by four-line combination differences that agree to within the spectrometer precision (9 MHz). Based on precision two-line ground-state combination differences and a symmetric top Hamiltonian, the B, DJ, and DJK rotational constants for the ground vibrational state of ND3H+ are determined with high precision for the first time. Approximate rotational constants for the ν1 excited state are also determined, with a band origin at 3316.8425(19) cm−1 and in remarkable (∼0.1 cm−1) agreement with high level anharmonic theoretical predictions by Guo and co-workers [J. Phys. Chem. A, 120...
- Subjects :
- Physics
010304 chemical physics
Spectrometer
Anharmonicity
General Physics and Astronomy
Infrared spectroscopy
01 natural sciences
Spectral line
Ion
symbols.namesake
Excited state
0103 physical sciences
symbols
Physical and Theoretical Chemistry
Atomic physics
Hamiltonian (quantum mechanics)
010303 astronomy & astrophysics
Doppler effect
Subjects
Details
- ISSN :
- 10897690 and 00219606
- Volume :
- 149
- Database :
- OpenAIRE
- Journal :
- The Journal of Chemical Physics
- Accession number :
- edsair.doi...........a5292351d485d52286bbb669f94ee2f6