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| Main Authors: | , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2504.10144 |
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| _version_ | 1866908318065229824 |
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| author | Coudert, Laurent H. Pirali, Olivier Martin-Drumel, Marie-Aline Chahbazian, Rosemonde Zou, Luyao Motiyenko, Roman A. Margulès, Laurent |
| author_facet | Coudert, Laurent H. Pirali, Olivier Martin-Drumel, Marie-Aline Chahbazian, Rosemonde Zou, Luyao Motiyenko, Roman A. Margulès, Laurent |
| contents | Open-shell non-rigid molecular systems exhibiting an internal rotation are likely candidates for a coupling between the spin angular momentum of the unpaired electron and the torsional motion. This electron spin-torsion coupling lacked both an experimental validation and a theoretical modeling. Here, the first experimental observation of the electron spin-torsion coupling is reported analyzing the pure rotational spectrum at millimeter wavelengths of the CH$_3$CO radical, a $^2Σ$ open-shell molecule displaying an internal rotation of its methyl group. To account for this coupling, a specific Hamiltonian incorporating the rotational, torsional, and electronic degrees of freedom is developed and allows us to reproduce the experimental spectrum. The present demonstration of the electron spin-torsion coupling will undoubtedly be key to future investigations of large open-shell molecules exhibiting a complex internal dynamics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_10144 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Evidence for electron spin-torsion coupling in the rotational spectrum of the CH$_3$CO radical Coudert, Laurent H. Pirali, Olivier Martin-Drumel, Marie-Aline Chahbazian, Rosemonde Zou, Luyao Motiyenko, Roman A. Margulès, Laurent Chemical Physics Open-shell non-rigid molecular systems exhibiting an internal rotation are likely candidates for a coupling between the spin angular momentum of the unpaired electron and the torsional motion. This electron spin-torsion coupling lacked both an experimental validation and a theoretical modeling. Here, the first experimental observation of the electron spin-torsion coupling is reported analyzing the pure rotational spectrum at millimeter wavelengths of the CH$_3$CO radical, a $^2Σ$ open-shell molecule displaying an internal rotation of its methyl group. To account for this coupling, a specific Hamiltonian incorporating the rotational, torsional, and electronic degrees of freedom is developed and allows us to reproduce the experimental spectrum. The present demonstration of the electron spin-torsion coupling will undoubtedly be key to future investigations of large open-shell molecules exhibiting a complex internal dynamics. |
| title | Evidence for electron spin-torsion coupling in the rotational spectrum of the CH$_3$CO radical |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2504.10144 |