stahrenberg_2001 ================ K\. Stahrenberg, Th\. Herrmann, K\. Wilmers, N\. Esser, W\. Richter and M\. J\. G\. Lee, "Optical properties of copper and silver in the energy range 2\.5\-9\.0 eV", Phys\. Rev\. B 64, 115111 \(2001\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1103/PhysRevB\.64\.115111 `__ **Source kind:** measurement **Recorded technique:** Spectroscopic ellipsometry in ultrahigh vacuum at room temperature on single\-crystal Cu\(110\) and Ag\(110\) \(aligned by Laue backscattering to 0\.1 deg, mechanically polished, cleaned in situ by cycles of 600 eV Ar\+ sputtering and annealing to 670 K, cleanliness checked by reflectance anisotropy spectroscopy\: the surface\-state features at 2\.1 eV on Cu\(110\) and 1\.7 eV on Ag\(110\)\)\. A rotating\-analyser ellipsometer with all components in the UHV chamber, on the 2m\-Seya\-Namioka beamline at BESSY I\: MgF2 prism polariser and rotating MgF2 analyser, angle of incidence 67\.5 deg, plane of incidence along \[1\-11\], 2\.5\-10 eV \(a quartz filter against second order at 2\.5\-4\.5 eV\) \(pp\. 115111\-2 to \-3\)\. The pseudodielectric function was corrected for surface roughness measured ex situ by AFM \(RMS 0\.41 nm for Cu, 0\.42 nm for Ag\) with a three\-layer model \(bulk, a Bruggeman 50 % void / 50 % bulk layer, vacuum\) \(p\. 115111\-4\)\. The paper also computes epsilon by FP\-LAPW DFT \(WIEN97, GGA, and an empirical exchange\-correlation potential fitted to Fermi\-surface data\) with final\-state scissors shifts\. **Materials in structured entries:** Ag, Cu **Dataset quantities:** extinction\_coefficient, permittivity\_real, refractive\_index **Contents:** 5 datasets; 0 formulas. Curation notes -------------- Journal article pages 115111\-1 to 115111\-8 = PDF pages 1\-8\. Identity checked against the first page\. No tables were extracted by the library, and the paper has none\: the pages were read\. WHAT THE PAPER HOLDS\. The measured dielectric functions of Cu and Ag are in figures only\: Fig\. 2 \(Cu\) and Fig\. 5 \(Ag\), epsilon\_1 and epsilon\_2 against photon energy, the measured pseudodielectric function \(dotted\), the roughness\-corrected bulk function \(solid\), the calculation \(dashed\), with Palik's \(Ref\. 1\) and Johnson and Christy's \(Ref\. 3\) values; Figs\. 4 and 7 are the energy derivatives d epsilon/dE\. No n, k or epsilon value is printed in the text or a table\. THE NUMBERS \(datasets n\_Ag, k\_Ag, n\_Cu, k\_Cu\)\. The only publication of the numbers is the refractiveindex\.info database, whose files main/Ag/nk/Stahrenberg\.yml and main/Cu/nk/Stahrenberg\.yml cite this paper with the note '\(Numerical data kindly provided by Prof\. Dr\. Norbert Esser\)' \(N\. Esser is the fourth author\)\. The files are kept in data/external/refractiveindex\_info/main/ \(commit c5c2f18, with their SHA\-256 in its PROVENANCE\.md; the Ag file is identical to solprop's pinned copy\)\. J\. C\. Travers chose to take them as this source's numbers \(2026\-09\-28\)\: they are recorded as this paper's data \(use = primary, no reproduced\_from\), with the database as the route, not as a comparison source\. They give n and k against the vacuum wavelength in um, five decimals, 0\.02 eV steps\: Ag 0\.12782\-0\.49594 um \(9\.70\-2\.50 eV, 361 rows\), Cu 0\.13776\-0\.49594 um \(9\.00\-2\.50 eV, 326 rows\), the ranges the paper measured \(Ag to 9\.7 eV, Cu to 9 eV\)\. The database gives no uncertainty and does not say whether the numbers are the measured pseudodielectric function or the roughness\-corrected one\. CHECKS OF THE NUMBERS AGAINST THE PAPER \(2026\-09\-28; epsilon = \(n \+ ik\)^2 computed from the files\)\. Ag epsilon\_1 crosses zero from negative to positive at 3\.788 eV and 7\.948 eV \(linear interpolation between rows\), the text's 3\.79 and 7\.95 eV \(dataset eps1\_zero\_Ag\), and from positive to negative at 4\.462 eV between them\. Maxima of d epsilon\_2/dE\: Cu at 4\.30 and 4\.70 eV \(the text\: 4\.3 and 4\.7 eV\); Ag at 4\.04 eV \(the text\: a peak at 4\.03 eV; the shoulders at 3\.84 and 4\.2 eV are not separate maxima of the numerical derivative\)\. Ag epsilon\_2 below 3\.8 eV is 0\.3\-0\.5 with n ~ 0\.07, the range where the paper says the noise increases\. The paper's comparison with the literature\: at 4\.49 eV the numbers give epsilon\_2 = 5\.81 \(Cu\) and 4\.12 \(Ag\) against Johnson and Christy's 4\.81 and 3\.75 \(the Weaver workbook's JC sheet\)\: 1\.0 and 0\.4 higher, as the text says \(1\.0\-1\.5 for Cu, 0\.5 for Ag\)\. ROUGHNESS CORRECTION\: not established\. Figs\. 2 and 5 show the measured \(dotted\) and corrected \(solid\) functions; read off the figure pixels \(a check, not data\), at the epsilon\_2 maxima the corrected curve is at about 6\.41 \(Cu, 4\.86 eV\) and 4\.17 \(Ag, 4\.48 eV\) and the measured one at about 6\.18 and 4\.09, while the numbers give 6\.25 and 4\.12\: between the two, nearer the measured curve for Cu; the stated corrections \(0\.2 and 0\.1\) are comparable with the line widths\. The Ag epsilon\_1 at 5\.0\-6\.1 eV \(\-0\.66 to \-0\.92\) follows the experimental curves \(which nearly coincide there\), not the calculation\. COMPARISONS \(2026\-09\-28\)\. solprop's silver table takes 0\.12782\-0\.20595 um from this database file\: its 185 rows there equal the file's exactly\. Against babar\_2015's website data \(Babar and Weaver's single crystals; interpolated\)\: Cu epsilon\_2 is 5\-17 % higher over 2\.5\-9 eV \(6\.27 against 5\.57 at 2\.5 eV, 3\.66 against 3\.26 at 6 eV\) and epsilon\_1 more negative by 0\.35\-1\.6; Ag epsilon\_2 higher by 0\.05\-0\.6 \(4\.12 against 3\.48 at 4\.5 eV, 3\.00 against 2\.69 at 6 eV\) and epsilon\_1 lower by 0\.25\-0\.52 above 4\.5 eV\. At 6 eV \(206\.6 nm\), where optmat's silver table now joins werner\_2009's REELS to Babar's Table 1, Stahrenberg's N = 1\.053 \+ 1\.422i lies between Babar's 1\.079 \+ 1\.247i and the REELS 0\.949 \+ 1\.548i \(copper\: 1\.027 \+ 1\.780i, Babar 1\.021 \+ 1\.599i, REELS 0\.962 \+ 1\.782i\)\. Silver was measured over 2\.5\-9\.7 eV \(p\. 115111\-6; the title says 2\.5\-9\.0 eV\); below the onset of d\-band absorption at 3\.84 eV the noise in epsilon\_2 increases 'since the sample is nonabsorbing and no compensator could be used'\. TEXT VALUES \(recorded where a quantity fits\)\: \- Ag\: 'epsilon\_1 crosses from negative to positive at 3\.79 eV and again at 7\.95 eV' \(p\. 115111\-6\)\: dataset eps1\_zero\_Ag\. The zero crossing 'observed at 7\.3 eV in Ref\. 1 \[Palik\] is shifted to 7\.95 eV in our data'\. \- Roughness corrections\: Cu, epsilon\_2 raised by at most 0\.2 at 4\.5 eV; Ag, by 0\.1 at 4\.5 eV\. The measured epsilon\_2 exceeds the literature's \(Refs\. 1 and 3, reflectance on films and polycrystals not measured in UHV\) by 1\.0\-1\.5 at 4\.5 eV for Cu and by 0\.5 at 4\.5 eV for Ag \(pp\. 115111\-4 and \-6\), attributed to the absence of adsorbed overlayers\. \- Features of d epsilon\_2/dE\: Cu maxima at 4\.3 and 4\.7 eV \(shoulder near 4\.4 eV in epsilon\_2\); Ag a peak at 4\.03 eV, a shoulder at 3\.84 eV and another at 4\.2 eV\. \- Calculation \(notes only\)\: scissors shifts Cu Delta\_6 = 0\.0, Delta\_7 = 0\.3 eV \(GGA\) and 0\.2, 0\.4 eV \(empirical potential\); Ag 0\.93, 0\.09 eV \(GGA\) and 0\.18, 0\.60 eV \(empirical\); broadening gamma = 0\.15 eV for Cu and 0\.025 eV for Ag; lattice constants 6\.8087 au \(Cu\) and 7\.7218 au \(Ag\) at room temperature\. **Recorded bibliographic identity status:** VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- stahrenberg\_2001/eps1\_zero\_Ag ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "eps1_zero_Ag", "material": "Ag", "table": "text", "quantity": "permittivity_real", "abscissa_unit": "eV", "use": "check", "parameters": { "form": "bulk", "technique": "spectroscopic ellipsometry (UHV, Ag(110))" } } 2 inline points in the source record. Text, p\. 115111\-6\: 'In silver, epsilon\_1 crosses from negative to positive at 3\.79 eV and again at 7\.95 eV \(see Fig\. 5\)'\. The energies are printed; the value 0 is the statement's \(epsilon\_1 = 0 there\), from the roughness\-corrected measurement\. A check on the zero crossings of a silver model, not a measured epsilon\_1 at a set energy\. stahrenberg\_2001/n\_Ag ~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "n_Ag", "material": "Ag", "file": "Ag/stahrenberg_2001__n_Ag.csv", "table": "data/external/refractiveindex_info/main/Ag/nk/Stahrenberg.yml", "quantity": "refractive_index", "abscissa_unit": "um", "use": "primary", "parameters": { "form": "bulk", "technique": "spectroscopic ellipsometry (UHV, Ag(110))" } } n of Ag\(110\), 0\.12782\-0\.49594 um \(9\.70\-2\.50 eV\), 361 rows, as the database file prints them \(numbers provided by N\. Esser to refractiveindex\.info; see notes\)\. Whether roughness\-corrected is not stated\. stahrenberg\_2001/k\_Ag ~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "k_Ag", "material": "Ag", "file": "Ag/stahrenberg_2001__k_Ag.csv", "table": "data/external/refractiveindex_info/main/Ag/nk/Stahrenberg.yml", "quantity": "extinction_coefficient", "abscissa_unit": "um", "use": "primary", "parameters": { "form": "bulk", "technique": "spectroscopic ellipsometry (UHV, Ag(110))" } } k of Ag\(110\), 0\.12782\-0\.49594 um \(9\.70\-2\.50 eV\), 361 rows, as the database file prints them \(see notes\)\. stahrenberg\_2001/n\_Cu ~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "n_Cu", "material": "Cu", "file": "Cu/stahrenberg_2001__n_Cu.csv", "table": "data/external/refractiveindex_info/main/Cu/nk/Stahrenberg.yml", "quantity": "refractive_index", "abscissa_unit": "um", "use": "primary", "parameters": { "form": "bulk", "technique": "spectroscopic ellipsometry (UHV, Cu(110))" } } n of Cu\(110\), 0\.13776\-0\.49594 um \(9\.00\-2\.50 eV\), 326 rows, as the database file prints them \(numbers provided by N\. Esser to refractiveindex\.info; see notes\)\. Whether roughness\-corrected is not stated\. stahrenberg\_2001/k\_Cu ~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "k_Cu", "material": "Cu", "file": "Cu/stahrenberg_2001__k_Cu.csv", "table": "data/external/refractiveindex_info/main/Cu/nk/Stahrenberg.yml", "quantity": "extinction_coefficient", "abscissa_unit": "um", "use": "primary", "parameters": { "form": "bulk", "technique": "spectroscopic ellipsometry (UHV, Cu(110))" } } k of Cu\(110\), 0\.13776\-0\.49594 um \(9\.00\-2\.50 eV\), 326 rows, as the database file prints them \(see notes\)\. 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.