Microwave spectra and nuclear quadrupole structure of the NH 3 –N 2 van der Waals complex and its deuterated isotopologues
| Autor: | Cristobal Perez, I.V. Tarabukin, Leonid A Surin, Melanie Schnell |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
010304 chemical physics Intermolecular force General Physics and Astronomy 010402 general chemistry 01 natural sciences 0104 chemical sciences symbols.namesake Deuterium Total angular momentum quantum number 0103 physical sciences Quadrupole symbols Isotopologue ddc:530 Rotational spectroscopy Physical and Theoretical Chemistry Atomic physics van der Waals force Hyperfine structure |
| Zdroj: | The Journal of Chemical Physics The journal of chemical physics 149(22), 224305 (2018). doi:10.1063/1.5063346 |
| ISSN: | 0021-9606 |
| DOI: | 10.1063/1.5063346 |
| Popis: | The journal of chemical physics 149(22), 224305 (2018). doi:10.1063/1.5063346 The microwave spectrum of the NH$_3$–N$_2$ van der Waals complex has been observed in a supersonic molecular jet expansion via broadband (2-8 GHz) chirped-pulse Fourier-transform microwave spectroscopy. Two pure rotational R(0) transitions (J = 1 − 0) with different hyperfine structure patterns were detected. One transition belongs to the (ortho)-NH$_3$–(ortho)-N$_2$ nuclear spin isomer in the ground K = 0 state reported earlier [G. T. Fraser et al., J. Chem. Phys. 84, 2472 (1986)], while another one is assigned to the (para)-NH$_3$–(para)-N$_2$ spin isomer in the K = 0 state not reported before (K is the projection of the total angular momentum J on the intermolecular axis). The complicated hyperfine structure arising from three quadrupole $^{14}$N nuclei of NH$_3$–N$_2$ was resolved for both transitions, and the quadrupole coupling constants associated with the NH$_3$ and N$_2$ subunits were precisely determined for the first time. These constants provided the dynamical information about the angular orientation of ammonia and nitrogen indicating that the average angle between the C$_3$ axis of NH$_3$ and the N$_2$ axis is about 66°. The average van der Waals bond lengths are slightly different for (ortho)-NH$_3$–(ortho)-N$_2$ and (para)-NH$_3$–(para)-N$_2$ and amount to 3.678 Å and 3.732 Å, respectively. Similar results for the deuterated isotopologues, ND$_3$–N$_2$, NHD$_2$–N$_2$, and NH$_2$D–N$_2$, and their nuclear spin isomers were also obtained thus confirming and extending the analysis for the parent NH$_3$–N$_2$ complex. Published by American Institute of Physics, Melville, NY |
| Databáze: | OpenAIRE |
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