{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"64bd83a8e25d32f9a86fb5229cf86ac7d3f595351f2dfcdd140deb5a0e242bfc","created":"2026-10-03T07:17:58Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"93299125f9ca5ebc456c8b6fcbc141a83641fa3adafcfd0bfe5fa168f3dc357b","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"chem.liquid-water.proton-solvation-structure","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"An extra hydrogen ion in water is shared among several water molecules, and two textbook shapes for this group compete. Which shapes actually occur, and which features of the broad infrared absorption belong to each, is still argued over.","posed_since":"","precise":"For an excess proton in liquid water at $300\\,\\mathrm{K}$, determine the distribution of its solvation structures (Eigen H9O4+, Zundel H5O2+ and intermediates) including nuclear quantum effects, and assign the broad infrared continuum and the ultrafast 2D-IR signatures to these structures. An answer is a simulation at near-quantum-chemical accuracy with path-integral nuclei that reproduces the linear and 2D-IR spectra and gives the structure distribution.","problem_ref":null,"references":"","settled_by":"Path-integral molecular dynamics on a coupled-cluster-quality potential reproducing linear and 2D-IR spectra of aqueous acids.","status_note":"","title":"Solvation structure and infrared signature of the excess proton","topic_ref":"8ba87b9cdffe8e8cf07699e738dbe5b7ba271aabae5cf5406a53e07fab8bdd45"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5abc703d75b642be2e1872942a783403269e5bb642535593caca1881e67629e0","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"7a9e0414b9534f26fa5c815ccde704fee50ac722a01a734fe39bf6b7393468c3","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"qDiN6dWh7PomPrLkIAZ5YyXYBemAFdtLB2O_u8wmFJKc-qGNxjtSSCic20IrM5kd6gVuMl5e_jMDBSieunvKBw"},"schema":"pubphys.envelope/1"},"record_hash":"5abc703d75b642be2e1872942a783403269e5bb642535593caca1881e67629e0","leaf_index":876}