zelikoff_1953 ============= M\. Zelikoff, K\. Watanabe and E\. C\. Y\. Inn, "Absorption coefficients of gases in the vacuum ultraviolet\. Part II\. Nitrous oxide", J\. Chem\. Phys\. 21, 1643 \(1953\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1063/1\.1698636 `__ **Source kind:** measurement **Recorded technique:** Photoelectric absorption as in Watanabe et al\. \(1953, watanabe\_1953\)\: a Baird 1 m vacuum monochromator \(entrance and exit slits 0\.05 mm, band width 0\.85 A\), scanned at 20 A/min, a hydrogen discharge, a 47 mm cell with cleaved LiF windows; N2O purified by ten fractional distillations \(impurities under about 0\.05 %, mass spectrometer\) at about 0\.01\-200 mm Hg; Beer's law held over a five\- to tenfold pressure range in all regions; scattered light and LiF fluorescence corrected; a few hundred wavelengths one to five angstroms apart, 1080\-2100 A \(p\. 1644\)\. **Materials in structured entries:** N2O **Dataset quantities:** absorption\_cross\_section, oscillator\_strength **Contents:** 6 datasets; 0 formulas. Curation notes -------------- Journal pages 1643\-1647 = PDF pages 2\-6 \(page 1 is the publisher's cover; page 2 opens with the end of the preceding article\)\. Identity checked against the page image \(pdf 2\)\: Zelikoff, Watanabe and Inn, 'Absorption Coefficients of Gases in the Vacuum Ultraviolet\. Part II\. Nitrous Oxide', J\. Chem\. Phys\. 21, 1643, received 7 April 1953\. N2O only\. The absorption coefficients are given only in Figs\. 1\-4 \(1080\-1220, 1220\-1380, 1380\-1605, 1605\-2100 A\); what the text states is recorded as points\. Quantity \(p\. 1644\)\: 'The absorption coefficient, k in cm^\-1 is defined by I/I0 = exp\(\-kx\) where x is the layer thickness of the absorbing gas in cm reduced to NTP' \(NTP not defined further; 0 C and 1 atm assumed, as in watanabe\_1953 and inn\_1953\)\. No conversion to cross sections is given; the datasets store k with scale = 1e18 / n0, n0 = 2\.6867801e19 cm^\-3 \(ideal gas\), to Mb\. Temperature not stated\. No accuracy statement \(only Beer's law over a five\- to tenfold pressure range\); wave numbers of the diffuse bands 'at best only approximate' \(p\. 1645\)\. Four regions after Duncan\: E\-F 1080\-1215 A \(continuum with maximum 'probably near 1080A', diffuse bands at 85350\-91800 cm^\-1, the strongest band at 84900 cm^\-1\), D 1215\-1380 A \(a continuum with maximum k = 2465 cm^\-1, a sharp band at 77400 cm^\-1 that 'probably contributes to the maximum value'\), C 1380\-1600 A \(a continuum with maximum 147 cm^\-1 at 68940 cm^\-1 under about twenty diffuse bands, the strongest at 68730 cm^\-1\) and B 1600\-2100 A \(weak continuum, maximum 3\.82 cm^\-1 at 1820 A\)\. Abstract \(p\. 1643\)\: 'Four continua were observed with maxima at 1820, 1450, 1285, and 1080A having f values of 0\.0015, 0\.0211, 0\.367, and 0\.1'\. The region D maximum's wavelength is the abstract's 1285 A \(Duncan's 77900 cm^\-1 = 1284 A, p\. 1645\)\. Not extracted\: Table I \(p\. 1645, image checked\), the bands of transition C\: N, calculated and observed wave numbers \(Eq\. 3, nu = 59590 \+ 1005 v' \- 30\.0 v'^2 \+ 0\.53 v'^3\) and relative intensities \(0\.06\-102\), band positions and relative strengths with no vocabulary quantity; Duncan's formula \(Eq\. 2\) and the Rydberg series \(Eq\. 1, nu = 102567 \- R/\(n \- 0\.92\)^2\) are spectroscopic, not dispersion formulas; the potential\-energy diagram \(Fig\. 5\)\. Reproduced\: Romand and Mayence's \(1949\) maxima \(dataset romand\_mayence\)\. **Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- zelikoff\_1953/continuum\_b\_maximum ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "continuum_b_maximum", "material": "N2O", "table": "text", "quantity": "absorption_cross_section", "unit": "Mb", "scale": 0.03721927208, "abscissa_unit": "angstrom", "wavelength_medium": "vacuum", "use": "primary" } 1 inline points in the source record. p\. 1646\: region B 'is one of weak continuous absorption with a maximum k value of 3\.82 cm^\-1 at 1820A', with weak very diffuse bands superposed\. scale = 1e18 / n0 \(NTP assumed\) to Mb\. Uncertainty not stated\. Romand and Mayence\: 3\.13 cm^\-1 at 1840 A \(romand\_mayence\)\. zelikoff\_1953/continuum\_c\_maximum ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "continuum_c_maximum", "material": "N2O", "table": "text", "quantity": "absorption_cross_section", "unit": "Mb", "scale": 0.03721927208, "abscissa_unit": "cm-1", "wavelength_medium": "vacuum", "use": "primary" } 1 inline points in the source record. p\. 1646\: 'There appears to be a relatively strong continuum underlying these bands with a maximum absorption coefficient of 147 cm^\-1 at 68 940' \(cm^\-1; the abstract's 1450 A\)\. The continuum under the diffuse bands, not the total absorption at a band \(the bands of Fig\. 3 reach about 200 cm^\-1\)\. scale = 1e18 / n0 \(NTP assumed\) to Mb\. Uncertainty not stated\. Romand and Mayence\: 118 cm^\-1\. zelikoff\_1953/continuum\_d\_maximum ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "continuum_d_maximum", "material": "N2O", "table": "text", "quantity": "absorption_cross_section", "unit": "Mb", "scale": 0.03721927208, "abscissa_unit": "angstrom", "wavelength_medium": "vacuum", "use": "primary" } 1 inline points in the source record. p\. 1645\: 'absorption of the Rydberg band probably contributes to the maximum value of the continuum \(k=2465 cm^\-1\)'; the position from the abstract \(maximum at 1285 A\)\. The observed maximum at 0\.85 A band width, including the sharp band at 77400 cm^\-1 that the authors think inflates it\. scale = 1e18 / n0 \(NTP assumed\) to Mb\. Uncertainty not stated\. zelikoff\_1953/band\_1178 ~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "band_1178", "material": "N2O", "table": "text", "quantity": "absorption_cross_section", "unit": "Mb", "scale": 0.03721927208, "abscissa_unit": "cm-1", "wavelength_medium": "vacuum", "use": "check" } 1 inline points in the source record. pp\. 1644\-1645 and abstract\: 'another band at 84 900 cm^\-1 which is the strongest ultraviolet absorption band observed for N2O\. Its k value at the maximum is 3010 cm^\-1' \(1178 A in the abstract\), a Rydberg member according to Duncan\. A band peak at 0\.85 A band width\: a check, not fitted \(as inn\_1953/band\_peak\_1119\)\. scale = 1e18 / n0 \(NTP assumed\) to Mb\. zelikoff\_1953/continuum\_f ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "continuum_f", "material": "N2O", "table": "text", "quantity": "oscillator_strength", "abscissa": "label", "use": "check" } 4 inline points in the source record. Oscillator strengths of the four continua, integrated with the formula of Part I \(watanabe\_1953\)\: B 0\.0015 over 46000\-65000 cm^\-1 \('The limits are probably not accurate, particularly the long wave limit', p\. 1646\); C 0\.0211 over 64250\-73000 cm^\-1 \(the continuum extrapolated to zero at both ends, p\. 1646\); D 0\.367 over 73000\-82250 cm^\-1, neglecting the Rydberg band \(p\. 1645\); E\-F 'estimated to be about 0\.1' from an inferred asymmetric continuum with maximum near 1080 A, excluding the bands \(p\. 1644\)\. The index \(1\-4\) only numbers the continua\. Checks\. zelikoff\_1953/romand\_mayence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "romand_mayence", "material": "N2O", "table": "text", "quantity": "absorption_cross_section", "unit": "Mb", "scale": 0.03721927208, "abscissa_unit": "angstrom", "wavelength_medium": "vacuum", "use": "reproduced", "reproduced_from": [ "J. Romand and J. Mayence, Compt. rend. 228, 998 (1949)" ] } 2 inline points in the source record. pp\. 1643, 1646\: Romand and Mayence \(photographic, 1390\-2200 A\) 'found the maxima to lie at 1450A and 1840A', with k = 118 cm^\-1 \(region C\) and 3\.13 cm^\-1 \(region B\); this work attributes the lower values to photographic detection\. Their reference state is not stated here \(NTP assumed, scale = 1e18 / n0 to Mb\)\. The original is not in the library \(missing\-O\)\. 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.