bieri_1977 ========== G\. Bieri, F\. Burger, E\. Heilbronner and J\. P\. Maier, "Valence Ionization Energies of Hydrocarbons", Helv\. Chim\. Acta 60, 2213 \(1977\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1002/hlca\.19770600714 `__ **Source kind:** compilation **Recorded technique:** He\(I alpha\) \(21\.22 eV\) and He\(II alpha\) \(40\.80 eV\) photoelectron spectroscopy \(Turner\-type cylindrical analysers, polystyrene\-film filtered He\(II\) source\), calibrated on the He\+ peaks at 24\.58 and 17\.02 eV, of 143 hydrocarbons; the tables collect the band maxima from this laboratory and from the literature, each column with its reference \(pp\. 2214\-2218, 2230\-2231\)\. **Materials in structured entries:** CH4 **Dataset quantities:** ionization\_energy **Contents:** 2 datasets; 0 formulas. Curation notes -------------- PDF pages 1\-21 = journal pages 2213\-2233\. Identity checked on the first page\. CH4 is the only curated species\. WHAT THE TABLES HOLD \(legend, p\. 2218; also p\. 2218 above it\)\: 'All ionization energies listed \(in eV\) refer to the position of the corresponding band maximum I\_j^m in the photoelectron spectrum of the hydrocarbon with an accuracy of \+\-0\.1 eV\. For all practical purposes I\_j^m ~ I\_j^v = vertical ionization energy\. \.\.\. adiabatic ionization energies I\_j^a are given in italics or in the footnotes, with an estimated accuracy of \+\-0\.02 eV\. Numbers in square brackets are the references and a star in square brackets \(\[\*\]\) indicates that these are new values determined in the course of this work\. A given reference number is valid also for all successive values in the column until a new reference number appears\.' The positions of maxima above 23 eV are uncertain by \+\-0\.2 eV or more \(p\. 2218\)\. CH4 \(first table of Section A, p\. 2218, tbl\_1342dbc497d6, cells only; image checked\)\: 1t2\: 13\.6^a, 14\.4^a, 15\.0^a \[17\]; 2a1\: 22\.9^b\. The only reference in the CH4 column is \[17\] = E\. Heilbronner, T\. B\. Jones and J\. P\. Maier, Helv\. Chim\. Acta 60, 1697 \(1977\), so by the legend every CH4 value is reproduced from it; none is marked \[\*\]\. Footnotes \(printed after the Section A tables, p\. 2222, page image checked\)\: 'a\) Band maxima of Jahn\-Teller distorted 2T\_d\-band \[sic, the 2T2 band\]\. The adiabatic ionization potential is I\_1^a = 12\.75 eV\. b\) Adiabatic ionization energy I\_1^a = 22\.39 eV\.' The footnoted adiabatic values are recorded as reproduced from the same reference \(the legend's rule; the footnotes cite nothing else\)\. BEARING\: the NIST WebBook's vertical CH4 value \(13\.6 \+\- 0\.1 eV, nist\_webbook\_2026/ vertical\_CH4\) cites this paper; it is Heilbronner, Jones & Maier's first Jahn\-Teller maximum\. The adiabatic 12\.75 eV of footnote a is 0\.14 eV above Berkowitz et al\.'s photoionisation onset \(berkowitz\_1987, 12\.61 eV\); that paper lists Brundle, Robin & Basch's 12\.75 eV among the earlier adiabatic values, which range from 12\.55 to 12\.78 eV\. NOT EXTRACTED\: the other 142 hydrocarbons \(C2H6, C2H4, C2H2 \.\.\.; out of scope\), the orbital assignment table of the C3 hydrocarbons \(p\. 2217\) and the spectra of Figs\. 1\-8\. **Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- bieri\_1977/vertical\_CH4 ~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "vertical_CH4", "material": "CH4", "file": "CH4/bieri_1977__vertical_CH4.csv", "table": "tbl_1342dbc497d6", "quantity": "ionization_energy", "unit": "eV", "abscissa": "label", "use": "reproduced", "reproduced_from": [ "heilbronner_1977" ], "parameters": { "kind": "vertical", "final_state": "the row's orbital hole: 1t2^-1 (X 2T2, Jahn-Teller maxima) or 2a1^-1 (2A1)" }, "uncertainty": { "absolute": 0.1, "level": "not stated" } } p\. 2218, CH4 column\: band maxima I^m ~ vertical ionisation energies\. Rows 1t2\_1, 1t2\_2, 1t2\_3\: the three maxima \(13\.6, 14\.4, 15\.0 eV\) of the Jahn\-Teller distorted 2T2 band \(footnote a\), the ionisation of the 1t2 orbital to CH4\+ X 2T2; row 2a1\: 22\.9 eV, the 2a1^\-1 \(2A1\) band\. Accuracy \+\-0\.1 eV \(legend\)\. Reference \[17\] for the whole column \(record notes\)\. The rows 1t2\_1 to 1t2\_3 equal heilbronner\_1977/vertical\_CH4 \(TC\-547\)\. The 2a1 row \(22\.9 eV\) is not in Heilbronner et al\. 1977, whose spectra end near 21 eV\: its origin is unknown\. bieri\_1977/adiabatic\_CH4 ~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "adiabatic_CH4", "material": "CH4", "table": "text", "quantity": "ionization_energy", "unit": "eV", "abscissa": "label", "use": "reproduced", "reproduced_from": [ "E. Heilbronner, T. B. Jones and J. P. Maier, Helv. Chim. Acta 60, 1697 (1977)" ], "parameters": { "kind": "adiabatic", "final_state": "the row's orbital hole: 1t2^-1 (X 2T2) or 2a1^-1 (2A1)" }, "uncertainty": { "absolute": 0.02, "level": "not stated" } } 2 inline points in the source record. Footnotes a and b of the Section A tables \(p\. 2222\)\: 'The adiabatic ionization potential is I\_1^a = 12\.75 eV' \(the 2T2 band\) and 'Adiabatic ionization energy I\_1^a = 22\.39 eV' \(the 2a1 band, footnote b of 22\.9\)\. Estimated accuracy of adiabatic values \+\-0\.02 eV \(legend, p\. 2218\)\. Attributed to the column's reference \[17\], but neither value is in Heilbronner et al\. 1977 \(heilbronner\_1977 prints no adiabatic energy; TC\-547\)\: their origin is unknown\. Formulas -------- No formulas are recorded. Corrections ----------- No dataset errata are recorded in this source record. Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register ` for the checks and decisions.