{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"dec9def61bfdce270d912185594568ac264fee03f95968e82ffe196034d9c0e6","created":"2026-10-03T07:17:58Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","a1cb891d6d5f9723a2901a04f187ba4d539a0a66b5982d5154cf11e0dc2e6ac4"],"salt":"c7b30f4fb9031300cb54b56a8c4d7687c02ec7e706e1a9294f8e3579cb114b6a","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"bio.supercooled-water.llcp-location","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"a1cb891d6d5f9723a2901a04f187ba4d539a0a66b5982d5154cf11e0dc2e6ac4","relation":"special_case"}],"plain":"If water's second critical point exists, its temperature and pressure must be pinned down. Model estimates disagree by tens of kelvin and by thousands of atmospheres.","posed_since":"","precise":"Assuming the LLCP exists, determine $(T_{c}, P_{c})$ for H2O. Published model results and extrapolations from experiment span roughly $T_{c} = 170 \\text{ to } 230\\,\\mathrm{K}$ and $P_{c}$ from about $0 \\text{ to } 2e9\\,\\mathrm{dyn}/\\mathrm{cm}^{2}$ ($0 \\text{ to } 2\\,\\mathrm{kbar}$), all approximate. An answer is a measured or reliably computed $(T_{c}, P_{c})$ with error bars, consistent with thermodynamic data at accessible conditions.","problem_ref":null,"references":"","settled_by":"Experimental location of the LLCP, or first-principles simulations including nuclear quantum effects whose predictions match measured response functions of supercooled water.","status_note":"A 2026 ultrafast X-ray experiment placed the critical temperature near $210 \\pm 8\\,\\mathrm{K}$ (You et al., Science 2026); the critical pressure and an independent confirmation remain open.","title":"Location of water's liquid-liquid critical point","topic_ref":"b1cabd44310015cc3941b7af0461d416e3c8ad464f6c3ad6f6fdbf54214bd97e"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"ab24ab5039676ea09cea6242356dc65d0fdd628b5014271d9b0d8b6f1be12037","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"f878e08593e3d26b90ef0d856bacba6feaac14218b666e97e48cf9ee157d4b89","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"1iWL0DdMVseFXK04vDmM_A3A19gNtmCz0kFcMBzAVP8oly36cswC0U2HVLmjKkMNrvVjef0nSYfJXgjol1LHAA"},"schema":"pubphys.envelope/1"},"record_hash":"ab24ab5039676ea09cea6242356dc65d0fdd628b5014271d9b0d8b6f1be12037","leaf_index":874}