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 · Catalogue · 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#
{
"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#
{
"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#
{
"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#
{
"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#
{
"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#
{
"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 review register for the checks and decisions.