{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"172e4a3589ea756272d7dea44e425f943b285a87e817f5511b7dd8761b7fe840","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"1f916216b6a5294139d952bcb20322cbaf47d3770d591b045f6e8e64cc2aab45","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"amo.molecular-parity-violation.first-energy-difference","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"The left- and right-handed forms of a chiral molecule should differ in energy by a tiny amount because of the weak force. No experiment has yet been sensitive enough to see it.","posed_since":"","precise":"$\\Delta E_{\\mathrm{PV}} = E(R) - E(S)$ between enantiomers, or the corresponding difference in a vibrational or rotational transition frequency, $\\Delta \\nu/\\nu$. The best direct bound is at the $1e-13$ level of relative frequency for the C-F stretch of CHFClBr (Daussy et al., PRL 1999), several orders of magnitude above predictions for that molecule; heavy-atom candidates (Re, Os, Ru, W complexes, scaling roughly as $Z^5$) are predicted to be larger. An answer is a nonzero $\\Delta \\nu$ or $\\Delta E_{\\mathrm{PV}}$ with significance above $5\\,\\sigma$, with sign and magnitude compared to theory.","problem_ref":null,"references":"","settled_by":"Ultrastable-laser vibrational spectroscopy of both enantiomers of a heavy-atom chiral molecule, or a time-resolved measurement of parity evolution in parity-selected states, reaching the predicted $\\Delta E_{\\mathrm{PV}}$.","status_note":"Experiments with cold molecular beams and heavy-atom candidates were still described as progress toward detection in 2025 (Phys. Chem. Chem. Phys. 2025).","title":"First measurement of the parity-violating energy difference between enantiomers","topic_ref":"f9dbbd39bd527922b0deb3484afb7d728e925b9b597bc403d39aba96df99f2c8"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"22717edb7eaa4cca51d6f1f83d7a782cf674c230e840dd8da8f942cc80b2d7a6","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"996ffb4d3ef83de9bdeea58340c26f3aa8a2ba333528eead52f8f1e7dc942a0e","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"ZiXHy4AxF19IkhqkpAGYorMcHDDvX7fWMuL6ejAUwh5LrQ_tamXEml-TVlS2xz2FDZJxPSCnVV2PPG0OrqvwBA"},"schema":"pubphys.envelope/1"},"record_hash":"22717edb7eaa4cca51d6f1f83d7a782cf674c230e840dd8da8f942cc80b2d7a6","leaf_index":423}