{"id":"d3d7e213-1e80-40f2-8c13-6fd82cf29ce5","arxiv_id":"2509.05509","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"A coupled-cluster calculation with QED corrections predicts the ionization potential and electron affinity of element 119 as 4.7839(56) eV and 0.6750(71) eV.","lead":"This paper calculates the ionization potential and electron affinity of element 119, a superheavy element not yet synthesized, using high-level relativistic quantum chemistry. The new values tighten previous estimates and give experimenters a clear target for the next search beyond oganesson.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Final EA depends on choosing SR-CCSD(T) over FS-CCSD; the 0.042 eV FS-CCSD gap in Table 5 is not closed by the +0.0028 eV high-order correction and is absent from the uncertainty budget.","rationale":"The paper is a careful composite calculation with a detailed uncertainty budget, and the IP value appears well supported: SR-CCSD(T) and FS-CCSD agree, QED is internally cross-checked with two implementations, and orbital-scheme differences collapse at the SR-CCSDT(Q) level. The load-bearing weakness is exclusively in the EA, and it is exactly the one the reader flagged: the paper must choose between a single-reference baseline giving 0.6759 eV and a Fock-space baseline giving 0.7176 eV. The quoted final EA inherits the SR choice, whose +0.0028 eV high-order correction is far too small to reconcile the two baselines. Since the FS-CCSD method is generally considered more appropriate for electron attachment to an open-shell atom, the unresolved 0.042 eV discrepancy is not a mere fine-tuning issue: it is larger than the entire quoted error bar. My proposed FS-CCSDT check would settle this directly. The reader's conditional verdict is therefore appropriate, and no change to that verdict is needed.","tokens_in":15640,"tokens_out":10695,"duration_ms":104984,"concrete_test":"Run a Fock-space coupled-cluster calculation with iterative triple excitations (FS-CCSDT, or an intermediate-Hamiltonian FS-CC with triples) for the 0h1p and 0h2p sectors, using the same active space and the final 41s36p25d22f9g6h5i basis as the FS-CCSD calculation. If the EA moves from 0.7176 eV downward by about 0.04 eV, the SR-CCSD(T)-based final value is supported; if it remains near 0.71 eV, the final EA is biased low by ~0.04 eV and the uncertainty must be enlarged accordingly. A cheaper first step is to perform the same FS-CCSDT test at the 2g2h basis level and check whether the triple-excitation correction to the FS-CCSD EA is of the required -0.04 eV order.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central EA claim is not robust because the paper adopts the SR-CCSD(T) baseline while its own final-basis FS-CCSD EA (0.7176 eV, Table 5) lies 0.042 eV above the SR-CCSD(T) value (0.6759 eV) — nearly six times the quoted EA uncertainty (0.0071 eV). The only explicitly computed high-order correction, SR-CCSDT(Q)-SR-CCSD(T) = +0.0028 eV (Section 2 and Table 5), moves the SR value to only 0.6787 eV and does not close the gap. The text attributes the remaining SR/FS difference to neglect of high-order excitations in FS-CCSD, but no FS-CCSDT or equivalent calculation is presented, and the claimed transfer of the 9-electron GRPP correction to the all-electron result cannot bridge a method spread roughly 15 times larger than the correction itself. The uncertainty budget in Table 4 includes basis-set, core, QED, and high-order contributions, but no term for this method dependence. Until that dependence is quantified, the value 0.6750(71) eV understates the true uncertainty in the EA. The IP is much less affected because SR-CCSD(T) and FS-CCSD agree to about 0.002 eV.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript reports a composite relativistic coupled-cluster study of the ionization potential (IP) and electron affinity (EA) of superheavy element 119 (E119). The baseline is all-electron single-reference relativistic CCSD(T) with a Dirac–Coulomb Hamiltonian, supplemented by basis-set extrapolation, Gaunt interaction, QED corrections from two model-QED operator implementations, and high-order correlation corrections (iterative triples and perturbative quadruples) obtained with a 9-electron generalized relativistic pseudopotential. The recommended values are IP = 4.7839(56) eV and EA = 0.6750(71) eV. The paper argues these are the most accurate theoretical estimates to date and provides a benchmark for experiments beyond oganesson.","tokens_in":16014,"tokens_out":3624,"duration_ms":40286,"significance":"If the central claim is sound, the paper delivers the most accurate theoretical IP and EA for element 119 and a careful uncertainty budget. Its strengths are genuinely ab initio character (no fitting to experimental target values), explicit treatment of high-order excitations up to perturbative quadruples, cross-checked QED corrections, and a detailed basis-set convergence analysis. The paper is therefore a useful reference for future experimental searches and for periodic-law trend studies. However, the central EA value depends on a methodological choice that is not fully justified, and the unresolved method spread is not reflected in the uncertainty budget.","major_comments":[{"comment":"The recommended EA is built on the SR-CCSD(T) baseline of 0.6759 eV, while the final-basis FS-CCSD value is 0.7176 eV, a 0.0417 eV gap that is about six times the quoted total EA uncertainty (0.0071 eV) and about fifteen times the computed SR-CCSDT(Q)−SR-CCSD(T) correction (+0.0028 eV). The text attributes this gap to neglect of high-order excitations in FS-CCSD, but no FS-CCSDT or equivalent multireference high-order calculation is presented that would close or quantify the gap. The uncertainty budget in Table 4 contains no term for reference-method dependence. As a result, the EA central value and its uncertainty are not robust. The authors should either provide a multireference high-order benchmark, conservatively incorporate the SR/FS method spread into the EA uncertainty, or otherwise justify why FS-CCSD is not the appropriate reference for E119−.","section":"§3.4, Table 5"},{"comment":"The high-order correlation correction is computed with a 9-electron GRPP pseudopotential in a compact contracted basis and then added to all-electron SR-CCSD(T) results obtained with the final uncontracted basis. This transferability assumption is load-bearing: the correction is small (+0.0028 eV for EA) and is being applied to a system with 102 correlated electrons. No test is reported of how the correction changes when the frozen-core/pseudopotential approximation is relaxed or when the basis is enlarged. The authors should provide at least a consistency check, e.g., comparing SR-CCSD(T) with the same GRPP/compact basis against the all-electron SR-CCSD(T) result, or estimating the basis and core dependence of the high-order correction itself.","section":"§2, SR-CCSDT(Q) paragraph"},{"comment":"The conclusion states that inclusion of high-order cluster amplitudes reduces the difference between the two orbital-construction schemes, but this is demonstrated only for the EA. For the IP, the difference between Set 1 and Set 2 is already small at SR-CCSD(T) and the high-order correction does not significantly change it. More importantly, the conclusion that the remaining discrepancy with Refs. [35,36,38] is primarily due to high-order excitations is not supported by the data in Table 5, since the paper’s own FS-CCSD value (0.7176 eV) lies close to those references and the high-order correction moves the SR value by only +0.0028 eV. This claim should be softened or backed by an explicit calculation.","section":"§4, Conclusion"}],"minor_comments":[{"comment":"Typographical and grammatical issues: 'ab initiostudy' is missing a space, and 'correlation are treated' should be 'correlations are treated'.","section":"Abstract"},{"comment":"'Berkeley' is misspelled as 'Berkely' in the list of laboratories.","section":"Introduction"},{"comment":"The FS-CCSD value in Table 5 (0.7176 eV) differs from the FS-CCSD value in Table 1 (0.7075 eV) obtained with a smaller basis. The text does not explain whether the Table 5 FS-CCSD row includes the same basis-set increments that were computed at the SR-CCSD(T) level or whether it comes from a separate FS-CCSD calculation. Clarifying this would improve readability.","section":"§3.4, Table 5"},{"comment":"The statement 'We estimate the uncertainty of each QED correction calculation to be ~10%' is reasonable but the basis for this estimate is not explained. Since the final uncertainty budget uses this 10% value, a one-sentence justification would be helpful.","section":"§3.3, Table 3"}],"recommendation":"major_revision","confidential_remarks":"The manuscript is a solid computational study with a careful uncertainty analysis, but the EA method dependence is a genuine load-bearing concern. The self-citation concentration is not unusual for this specialized area and is not, in itself, a problem. If the authors can provide a multireference high-order benchmark or otherwise convincingly account for the SR/FS method spread, the paper could become acceptable. As it stands, the quoted EA uncertainty appears understated, so major revision is warranted."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Bottom line: the IP is probably the most reliable estimate yet for E119, and the high-order correlation treatment is a genuine step up. The EA is the problem child: the paper's own FS-CCSD value sits 0.042 eV above the adopted SR-CCSD(T) baseline, and the computed high-order correction does not close that gap. The quoted 0.6750(71) eV therefore understates the real uncertainty.\n\nWhat the paper does well: it is the first calculation of E119 IP/EA that includes iterative triples and perturbative quadruples (SR-CCSDT(Q)), using a compact GRPP basis designed for the job. The QED and Gaunt corrections are evaluated with two independent model QED operators and several correlation methods, and the results are consistent. The IP is robust: different orbital schemes, basis sets, FS-CCSD and SR-CCSD(T) all land within a few meV, and the final 4.7839(56) eV agrees with earlier estimates. The uncertainty budget is transparent and itemized.\n\nThe soft spot is exactly what the stress-test note says. In Table 5, FS-CCSD gives EA = 0.7176 eV; SR-CCSD(T) gives 0.6759 eV. The SR-CCSDT(Q) correction is only +0.0028 eV, moving SR-CCSD(T) to 0.6787 eV. The text attributes the remaining 0.04 eV to neglected high-order excitations in FS-CCSD, but no FS-CCSDT calculation is shown. That attribution is an assertion, not a demonstrated result. Table 4's error budget includes basis, core, QED, and high-order terms, but no term for this method dependence. It's not a fatal flaw — the EA is still positive and in the range of earlier estimates — but the uncertainty should be expanded by something like 0.04 eV or the single-reference choice explicitly defended. The two-orbital-scheme convergence in Table 1 is encouraging (the EA converges to ~0.678 eV after SR-CCSDT(Q)), but FS-CCSD is a different reference and the gap persists.\n\nMinor points: the QED correction to the EA is 0.0032 eV, much smaller than the 0.0123 eV in Ref. [36]; the paper notes this but doesn't resolve it. Self-citation is heavy but appropriate given the group developed the methods.\n\nWho benefits: specialists in superheavy element atomic physics and relativistic quantum chemistry. The IP is a solid reference; the EA is usable if the caveat is attached. A serious referee should ask for either an FS-CCSDT calculation or a quantified method-dependence estimate, and that is a realistic revision, not a rejection.","headline":"IP is solid; EA has an unresolved 0.042 eV method gap that the uncertainty budget misses.","tokens_in":16468,"tokens_out":3452,"would_cite":true,"duration_ms":33689,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"Superheavy element 119's ionization potential and electron affinity are pinned to 4.7839(56) eV and 0.6750(71) eV by a composite relativistic coupled-cluster calculation that includes the Gaunt interaction and quantum electrodynamic correct","keywords":["element 119","superheavy elements","ionization potential","electron affinity","relativistic coupled cluster","Gaunt interaction","QED corrections","periodic law"],"falsifier":"A future experiment on synthesized element 119 that measures the first ionization threshold outside 4.7839 ± 0.0056 eV, or a photodetachment measurement of the anion giving an electron affinity outside 0.6750 ± 0.0071 eV, would falsify the central claim.","tokens_in":15633,"feed_emoji":"⚛️","tokens_out":3256,"duration_ms":36870,"temperature":0.7,"pith_summary":"The paper attempts to establish the most accurate theoretical values yet for how tightly element 119 holds its outermost electron, both when the atom is ionized and when it forms a negative ion. It combines high-order relativistic coupled-cluster correlation, the Gaunt part of the Breit interaction, and QED radiative corrections into a single uncertainty budget. If correct, these values give experimenters concrete numbers to compare against once element 119 is synthesized, and they sharpen the picture of how periodic-law trends behave beyond oganesson.","feed_headline":"Element 119's ionization energy pinned to 4.7839 eV","feed_subtitle":"New calculation adds QED and high-order correlation to give experiment-ready targets for the next superheavy element.","key_machinery":"The argument rests on a composite computational protocol. A large-basis all-electron SR-CCSD(T) calculation provides the baseline, while the expensive iterative-triples and perturbative-quadruples correction is computed separately using a 9-electron generalized relativistic pseudopotential (GRPP) with a compact atomic-natural-orbital-type basis. Gaunt corrections enter through an X2Cmmf Hamiltonian, and QED corrections are added via model QED operators in two independent implementations. The protocol's job is to make high-order correlation effects affordable while keeping the final values tied to a fully relativistic, all-electron treatment.","core_discovery":"The paper's central claim is that the first ionization potential of element 119 is 4.7839(56) eV and its electron affinity is 0.6750(71) eV. These values come from an all-electron relativistic SR-CCSD(T) baseline, to which the authors add first-time corrections for iterative triple and perturbative quadruple cluster amplitudes, the Gaunt electron-electron interaction, and QED self-energy and vacuum-polarization effects. The paper also reports a detailed uncertainty budget, with the dominant errors coming from high-angular-momentum basis functions and high-order correlation effects.","pith_inferences":["If the single-reference result survives experimental scrutiny, Fock-space CCSD appears to overestimate the electron affinity of element 119 by roughly 0.03-0.04 eV, suggesting that higher excitations are mandatory for the two-electron attachment sector.","The compact-basis correction strategy demonstrated here could be transferred directly to element 120 and other superheavy atoms, where all-electron CCSDT(Q) is out of reach but the high-order correction may be captured in a frozen-core pseudopotential space.","A readily testable extension would be to apply the same composite scheme to the known lighter homologs of element 119, where measured IPs and EAs exist, to calibrate the size of the systematic error before the superheavy experiment arrives."],"forward_implications":["If these values are correct, element 119's electron affinity is firmly positive, meaning the E119 minus anion is a bound species despite the atom sitting in group 1.","The predicted ionization threshold at roughly 4.78 eV gives a concrete target for laser-ionization or mass-spectrometric experiments once element 119 is produced.","The first-time evaluation of triple and quadruple excitation contributions shows that high-order correlation shifts the electron affinity by several hundredths of an electron volt, so earlier Fock-space double-excitation results are not the final word.","The discrepancy between the final electron affinity and the FS-CCSD value makes the anion a useful test case for judging when single-reference versus Fock-space coupled-cluster treatments are reliable in superheavy systems."],"supporting_citations":[{"why":"Supplies the optimized basis set, the single-reference and Fock-space baseline values, and the previous uncertainty estimate that this work extends.","marker":"[34]"},{"why":"Defines the relativistic SR-CCSD(T) method that serves as the all-electron baseline for the final IP and EA.","marker":"[48]"},{"why":"Provides the SR-CCSDT(Q) method used to evaluate iterative triple and perturbative quadruple excitation contributions.","marker":"[56]"},{"why":"Underlies the generalized relativistic pseudopotential framework in which the high-order correlation corrections are computed.","marker":"[57–60]"},{"why":"Supplies the specific GRPP for element 119 with 9 active electrons used for the SR-CCSDT(Q) calculations.","marker":"[61]"},{"why":"Provide the model QED operator implementation used to evaluate vacuum polarization and self-energy contributions.","marker":"[70, 71]"},{"why":"Provides the alternative QED operator implementation used to cross-check the QED correction at SR-CCSD(T) and FS-CCSD levels.","marker":"[81]"},{"why":"Earlier CI-DFS+MBPT result for IP and EA which is compared with the final recommended values.","marker":"[33]"}],"fun_headline_variants":["Element 119's electron affinity computed: 0.6750 eV","QED corrections refine element 119's ionization potential","Element 119: IP=4.7839 eV, EA=0.6750 eV","High-order correlation tightens element 119's electron affinity"],"cache_read_input_tokens":2688,"weakest_assumption_plain":"The high-order correlation correction computed with the 9-electron pseudopotential and compact basis transfers quantitatively to the all-electron SR-CCSD(T) result, and the single-reference treatment, rather than Fock-space CCSD, is the correct reference for the anion E119-.","fun_headline_variants_meta":{"raw":{"variants":["Element 119's electron affinity computed: 0.6750 eV","QED corrections refine element 119's ionization potential","Element 119: IP=4.7839 eV, EA=0.6750 eV","High-order correlation tightens element 119's electron affinity"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000667,"raw_usage":{"total_tokens":2822,"prompt_tokens":626,"completion_tokens":2196,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":370,"completion_tokens_details":{"reasoning_tokens":2119}},"tokens_in":370,"tokens_out":2196,"duration_ms":16335,"temperature":1.0,"reasoning_tokens":2119,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-05T05:23:38.267526+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A future experiment on synthesized element 119 that measures the first ionization threshold outside 4.7839 ± 0.0056 eV, or a photodetachment measurement of the anion giving an electron affinity outside 0.6750 ± 0.0071 eV, would falsify the central claim.","supporting_citations":[{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the optimized basis set, the single-reference and Fock-space baseline values, and the previous uncertainty estimate that this work extends."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Defines the relativistic SR-CCSD(T) method that serves as the all-electron baseline for the final IP and EA."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the specific GRPP for element 119 with 9 active electrons used for the SR-CCSDT(Q) calculations."},{"cited_title":"Pyykk¨ o, Chem","cited_arxiv_id":null,"evidence_quote":"Provides the alternative QED operator implementation used to cross-check the QED correction at SR-CCSD(T) and FS-CCSD levels."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Earlier CI-DFS+MBPT result for IP and EA which is compared with the final recommended values."}],"review_version":1}