{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"177be12d07ad45b9f50985c4086f9943fb739010e306d68a02afeb941eedfb0d","created":"2026-10-03T07:17:58Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"5818c316534c78021e799985aea55c4643f026033d0765dbd512c7752462356f","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"chem.dft-functionals.fundamental-gap","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"Standard functionals underestimate the energy needed to add or remove an electron, which sets how well a material conducts or absorbs light. Fixes exist but each must be retuned for each material.","posed_since":"","precise":"Find a generalized Kohn-Sham functional with no system-specific tuning that gives the fundamental gap $I - A$ ($I = \\text{ionization energy}, A = \\text{electron affinity}$) of molecules (the GW100 set of ionization potentials and electron affinities and similar sets) and the band gap of semiconductors and insulators (Si to LiF) with mean absolute error below $0.2\\,\\mathrm{eV}$. An answer is such a functional or an argument that tuning-free accuracy at this level requires orbital-dependent nonlocal terms of a specified type.","problem_ref":null,"references":"","settled_by":"Benchmark against experimental and many-body (GW, coupled-cluster) gaps across molecules and solids with a single parameter set.","status_note":"","title":"System-independent functional giving fundamental gaps of molecules and solids","topic_ref":"3c4f63964447b45aecf4c4997f101268b15cc64d8f6c4f7f7f8c32e958440823"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"7217d48d4899cdad0f316242442134ad9b341e60c7246bbc21821a54f27a533f","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"99074afbf23f25dc3408d1849e2df331d25017bfe7d67292c6d4351fba06ba82","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"kJEy3KVeCX7-o5r4nNyNYjkLdFW_YlRzWiqK9DMqnvr2nN8JZ04xYvJhqtAzLDbLQVH1rOUTN32Gvj2RfGGJDQ"},"schema":"pubphys.envelope/1"},"record_hash":"7217d48d4899cdad0f316242442134ad9b341e60c7246bbc21821a54f27a533f","leaf_index":859}