{"paper":{"title":"Rotational energy levels in the ground vibrational state of methane with kHz-level accuracy from comb-referenced double-resonance and Lamb-dip spectroscopies","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"Methane ground-state rotational levels up to J=12 are now known to kHz accuracy","cross_cats":[],"primary_cat":"physics.chem-ph","authors_text":"Aleksandra Foltynowicz, Hajima Inaba, Hiroyuki Sasada, Isak Silander, Kevin K. Lehmann, Sho Okubo, Vinicius Silva de Oliveira","submitted_at":"2026-05-13T06:33:29Z","abstract_excerpt":"Methane is a key spherical-top molecule, yet restrictive selection rules for one-photon transitions have prevented determination of its ground state (GS) energies with state-of-the-art kHz-level accuracy. We report the GS rotational energy level differences with kHz-level accuracy from two frequency-comb-referenced sub-Doppler methods: optical-optical double-resonance spectroscopy in the ${\\Lambda}$-type configuration, and Lamb-dip spectroscopy of allowed and forbidden transitions. A Hamiltonian fit to the data yields GS term values with rotational numbers up to $\\it{J}$ = 12 with kHz level ac"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"A Hamiltonian fit to the data yields GS term values with rotational numbers up to J = 12 with kHz level accuracy.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The effective Hamiltonian expansion contains all relevant interaction terms up to the order needed for J=12 and that systematic errors in the frequency measurements remain below the claimed kHz uncertainty.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Ground-state rotational term values of methane up to J=12 determined with kHz accuracy via frequency-comb-referenced double-resonance and Lamb-dip spectroscopies.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Methane ground-state rotational levels up to J=12 are now known to kHz accuracy","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"b4b42659f9b1d9538170b6b72013e4d14c7910fe17d18cda66f94a839967f7b6"},"source":{"id":"2605.13060","kind":"arxiv","version":1},"verdict":{"id":"b1437276-3de2-4815-93b9-01b6b7f7a15d","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-14T02:08:41.110093Z","strongest_claim":"A Hamiltonian fit to the data yields GS term values with rotational numbers up to J = 12 with kHz level accuracy.","one_line_summary":"Ground-state rotational term values of methane up to J=12 determined with kHz accuracy via frequency-comb-referenced double-resonance and Lamb-dip spectroscopies.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The effective Hamiltonian expansion contains all relevant interaction terms up to the order needed for J=12 and that systematic errors in the frequency measurements remain below the claimed kHz uncertainty.","pith_extraction_headline":"Methane ground-state rotational levels up to J=12 are now known to kHz accuracy"},"references":{"count":16,"sample":[{"doi":"","year":1983,"title":"R. W. P. Drever, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, Appl. Phys. B 31, 97 (1983)","work_id":"9fa37c7f-89c9-43f3-b238-5095c2033556","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2017,"title":"G. Sobon, T. Martynkien, P. Mergo, L. Rutkowski, and A. Foltynowicz, Opt. Lett. 42, 1748 (2017)","work_id":"fc85e789-5cb6-47bf-aca8-d83008a58a7f","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2025,"title":"Silva de Oliveira, A","work_id":"c5db7392-97d2-46fc-a42f-7dd2803e9276","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"K. Kefala, V. Boudon, S. N. Yurchenko, and J. Tennyson, J. Quant. Spectr. Rad. Transf. 316, 108897 (2024)","work_id":"7ac08a04-aaf0-4c2f-a588-688af008124b","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"J. Tennyson et al., J. Quant. Spectr. Rad. Transf. 326, 109083 (2024)","work_id":"f1a3a4b3-5f22-4abe-83c6-fb8baaf4d4c7","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":16,"snapshot_sha256":"c4688a7485b0aa390dc1bca9f1afbd4e2dd82a3ba84431627eea8e8aa1030129","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}