eshel_2016#
B. Eshel, C. A. Rice and G. P. Perram, “Pressure broadening and shift rates for Ar (s-p) transitions observed in an Ar-He discharge”, J. Quant. Spectrosc. Radiat. Transfer 179, 40-50 (2016)
Source record · Catalogue · Review register
DOI: 10.1016/j.jqsrt.2016.03.006
Source kind: measurement
Recorded technique: Tunable diode laser absorption spectroscopy (New Focus Velocity 6314, 792-802 nm, 300 kHz linewidth, wavemeter against a stabilised HeNe to 10 MHz, below saturation) of the metastable- and resonance-level absorption lines 801.699 nm (s5 -> p8), 800.836 nm (s4 -> p6) and 795.036 nm (s3 -> p4) of argon in a 13.56 MHz capacitively coupled discharge (10 W, alumina tube 0.15 in i.d., flowing 99.999 % Ar-He mixtures of 2.5, 5, 10 and 25 % Ar) at 10-160 Torr total pressure (tables; 10-200 Torr in the text). Each absorbance profile is fitted with a Voigt profile, the Doppler width constrained to 888 +- 25 MHz (440 +- 20 K, the mean of the unconstrained fits below 60 Torr); the Lorentzian FWHM and the line centre are fitted linearly against the total pressure. Uncertainties are the 95 % confidence intervals of the linear fits.
Materials in structured entries: Ar
Dataset quantities: pressure_line_coefficient
Contents: 10 datasets; 0 formulas.
Curation notes#
J. Quant. Spectrosc. Radiat. Transfer 179, 40-50 (2016) = PDF pages 1-11 (journal page = PDF page + 39). Identity checked on the first page (PDF p. 1: journal, volume, pages, title, authors, Air Force Institute of Technology; received 7 December 2015, accepted 1 March 2016, available online 17 March 2016; DOI) on 2026-10-12. Tables 1 and 2 checked cell by cell against their images.
ONE-PHOTON 4s-4p LINES, NOT OEP 8’s COHERENCE. These are one-photon absorption lines from the 4s levels to the 4p levels, broadened and shifted by an Ar-He mixture. OEP 8 needs the dephasing of the ground-to-4p two-photon coherence by argon; the 4s-4p line width also contains the 4s level’s broadening and the Ar-He mixture’s helium part, so nothing for the two-photon coherence is derived from these values.
LEVELS (Fig. 1, Paschen and Racah labels with NIST’s energies; NIST Ar_I_levels.tsv). s5 = 4s[3/2]2 = 3p5(2P*3/2)4s 2[3/2]* J = 2 (93143.76 cm-1); s4 = 4s[3/2]1 = 3p5(2P*3/2)4s 2[3/2]* J = 1 (93750.60); s3 = 4s’[1/2]0 = 3p5(2P*1/2)4s 2[1/2]* J = 0 (94553.67); p8 = 4p[5/2]2 = 3p5(2P*3/2)4p 2[5/2] J = 2 (105617.27); p6 = 4p[3/2]2 = 3p5(2P*3/2)4p 2[3/2] J = 2 (106237.55); p4 = 4p’[3/2]1 = 3p5(2P*1/2)4p 2[3/2] J = 1 (107131.71). The upper levels p8 and p6 are two of OEP 8’s two-photon levels (4p[5/2]2 and 4p[3/2]2); p4 is one of baig_2008’s photoionised levels. The printed wavelengths are NIST’s vacuum wavelengths (801.6990, 800.8359, 795.0362 nm; Ar_I_lines_nir.tsv; script report). The paper misprints the lines as ‘794.036 nm’ (pp. 47-49), ‘800.036 nm’ (Fig. 6 and 10 captions) and ‘801.669’ (p. 45).
WIDTH CONVENTION. Eq. (2) writes the Lorentzian with (Delta nu_L / 2)^2, so Delta nu_L is the FWHM in ordinary frequency, and Eq. (9) defines the rate by Delta nu_L = gamma P; Table 1’s heading calls the rate ‘2 gamma’. The tabulated values are the slopes of the Lorentzian FWHM (Fig. 6, whose caption gives the 10 % row), so width = fwhm; the ‘2 gamma’ label is the convention in which gamma is the half width. Eq. (10): nu_c = nu_0 + beta P, beta positive for a blue shift (Table 2: ‘Negative rates are red-shifts’), the vocabulary’s sign. Rates are per Torr of total pressure of the mixture.
TAKEN (tools/extract/eshel_2016.py; Tables 1 and 2, ‘This work’ rows): broadening_mix* and shift_mix* for 2.5, 5, 10 and 25 % Ar in He, rows the three lines (800.836 nm not measured at 25 %), use primary, uncertainties the 95 % confidence intervals as printed. Inline (p. 47 and Fig. 9 caption): the authors’ separation of the broadening into Ar-Ar and Ar-He rates by a linear fit in the Ar fraction, gamma = gamma_Ar f_Ar + gamma_He (1 - f_Ar), ‘Ar-Ar rates of 8, 38 and 12 MHz/Torr and Ar-He rates of 16, 16 and 19 MHz/Torr’ (broadening_self_fit, broadening_He_fit), use check: the authors call it ‘an estimate’, the Ar-Ar rates are an extrapolation from 2.5-25 % Ar to pure argon, and no uncertainty is given. No shift separation is given (the paper says shift rates in a mixture do not add, p. 49).
CHECKED (2026-10-12). The 10 % Ar rows against the abstract and the captions of Figs. 6 and 7 (script check). The Ar-He decomposition against Table 1’s Ar-He literature row (Copley, ref. 22, 460 K): 801.699 nm 16.40 +- 1.64 against the fit’s 16; 795.036 nm 13.88 +- 1.39 against 19.
FINDINGS. The fitted Ar-Ar rate of the 801.699 and 795.036 nm lines (8 and 12 MHz/Torr at 440 K) is about half their Ar-He rate; the 800.836 nm line (resonance lower level s4) has the larger Ar-Ar rate, 38 MHz/Torr, which the paper ascribes to resonance broadening of s4. The paper’s literature rows of Ar-Ar broadening at 353-3900 K, scaled to 440 K by T^-0.7, give 9.6-14.9 MHz/Torr for 801.699 and 795.036 nm (fit: 8 and 12) and 20.1-25.0 for 800.836 nm (fit: 38); the authors call the separation ‘in good agreement’ after scaling. The Einstein A values used (p. 42; 1.86e7, 4.90e6, 9.28e6 s-1, ref. 35, ‘25 %’) are NIST’s (1.86e7, 4.9e6, 9.3e6) and are not taken.
NOT TAKEN. The literature rows of Tables 1 and 2 (refs. 21-24, 27: Copley and Camm 1974, Copley 1976, Vallee et al. 1977, Moussounda and Ranson 1987, Aeschliman et al. 1976), quoted with the authors’ T^-0.7 scaling; the Lorentzian and Doppler widths and shift at 100 Torr (1879 +- 2 MHz, 889 MHz, 610.9 +- 0.6 MHz, p. 44); the zero-pressure widths (117 +- 44 to 227 +- 33 MHz); the line-centre cross sections (p. 43); the Stark estimates (p. 45); Figs. 3-10 (the rates are printed); the phase-changing cross sections of Fig. 10 (no quantity). No two-photon data.
Recorded bibliographic identity status: VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
eshel_2016/broadening_mix2p5#
{
"id": "broadening_mix2p5",
"material": "Ar",
"file": "Ar/eshel_2016__broadening_mix2p5.csv",
"table": "tbl_45fc5023b655",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "broadening",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "fwhm",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 2.5 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 1 (p. 47), ‘Pressure broadening rate, 2 gamma (MHz/Torr)’, row ‘2.5% Ar’ (this work): 801.699, 800.836 and 795.036 nm, per Torr of the total pressure of the 2.5 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The Lorentzian FWHM rate in ordinary frequency (record notes). One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/broadening_mix5#
{
"id": "broadening_mix5",
"material": "Ar",
"file": "Ar/eshel_2016__broadening_mix5.csv",
"table": "tbl_45fc5023b655",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "broadening",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "fwhm",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 5 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 1 (p. 47), ‘Pressure broadening rate, 2 gamma (MHz/Torr)’, row ‘5% Ar’ (this work): 801.699, 800.836 and 795.036 nm, per Torr of the total pressure of the 5 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The Lorentzian FWHM rate in ordinary frequency (record notes). One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/broadening_mix10#
{
"id": "broadening_mix10",
"material": "Ar",
"file": "Ar/eshel_2016__broadening_mix10.csv",
"table": "tbl_45fc5023b655",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "broadening",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "fwhm",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 10 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 1 (p. 47), ‘Pressure broadening rate, 2 gamma (MHz/Torr)’, row ‘10% Ar’ (this work): 801.699, 800.836 and 795.036 nm, per Torr of the total pressure of the 10 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The Lorentzian FWHM rate in ordinary frequency (record notes). One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/broadening_mix25#
{
"id": "broadening_mix25",
"material": "Ar",
"file": "Ar/eshel_2016__broadening_mix25.csv",
"table": "tbl_45fc5023b655",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "broadening",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "fwhm",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 25 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 1 (p. 47), ‘Pressure broadening rate, 2 gamma (MHz/Torr)’, row ‘25% Ar’ (this work): 801.699 and 795.036 nm (800.836 nm: ‘-’), per Torr of the total pressure of the 25 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The Lorentzian FWHM rate in ordinary frequency (record notes). One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/shift_mix2p5#
{
"id": "shift_mix2p5",
"material": "Ar",
"file": "Ar/eshel_2016__shift_mix2p5.csv",
"table": "tbl_6d2606d4248c",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "shift",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "none",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 2.5 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 2 (p. 49), ‘Pressure shifting rate, beta (MHz/Torr)’, negative = red, row ‘2.5% Ar’ (this work): 801.699, 800.836 and 795.036 nm, per Torr of the total pressure of the 2.5 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The line-centre shift in ordinary frequency, positive to the blue. One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/shift_mix5#
{
"id": "shift_mix5",
"material": "Ar",
"file": "Ar/eshel_2016__shift_mix5.csv",
"table": "tbl_6d2606d4248c",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "shift",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "none",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 5 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 2 (p. 49), ‘Pressure shifting rate, beta (MHz/Torr)’, negative = red, row ‘5% Ar’ (this work): 801.699, 800.836 and 795.036 nm, per Torr of the total pressure of the 5 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The line-centre shift in ordinary frequency, positive to the blue. One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/shift_mix10#
{
"id": "shift_mix10",
"material": "Ar",
"file": "Ar/eshel_2016__shift_mix10.csv",
"table": "tbl_6d2606d4248c",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "shift",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "none",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 10 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 2 (p. 49), ‘Pressure shifting rate, beta (MHz/Torr)’, negative = red, row ‘10% Ar’ (this work): 801.699, 800.836 and 795.036 nm, per Torr of the total pressure of the 10 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The line-centre shift in ordinary frequency, positive to the blue. One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/shift_mix25#
{
"id": "shift_mix25",
"material": "Ar",
"file": "Ar/eshel_2016__shift_mix25.csv",
"table": "tbl_6d2606d4248c",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "95 % confidence"
},
"parameters": {
"effect": "shift",
"transition": "the rows: 801.699 nm (s5 -> p8, 4s[3/2]2 - 4p[5/2]2), 800.836 nm (s4 -> p6, 4s[3/2]1 - 4p[3/2]2), 795.036 nm (s3 -> p4, 4s'[1/2]0 - 4p'[3/2]1), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "none",
"frequency_variable": "ordinary",
"perturber": "Ar-He mixture, 25 % Ar in He (rate per unit total pressure)",
"temperature_k": 440,
"pressure_range": "10-160 Torr",
"method": "tunable diode laser absorption in an RF discharge, Voigt fits with the Doppler width fixed (440 K), linear fit against pressure"
}
}
Table 2 (p. 49), ‘Pressure shifting rate, beta (MHz/Torr)’, negative = red, row ‘25% Ar’ (this work): 801.699 and 795.036 nm (800.836 nm: ‘-’), per Torr of the total pressure of the 25 % Ar in He mixture at 440 +- 20 K, 10-160 Torr. The line-centre shift in ordinary frequency, positive to the blue. One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/broadening_self_fit#
{
"id": "broadening_self_fit",
"material": "Ar",
"table": "text",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "check",
"uncertainty": {
"level": "not stated"
},
"parameters": {
"effect": "broadening",
"transition": "the rows: 801.699 nm (s5 -> p8), 800.836 nm (s4 -> p6), 795.036 nm (s3 -> p4), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "fwhm",
"frequency_variable": "ordinary",
"perturber": "self",
"temperature_k": 440,
"pressure_range": "10-160 Torr (mixtures of 2.5-25 % Ar)",
"method": "linear fit of the mixtures' broadening rates against the Ar fraction (Ar-Ar part)"
}
}
3 inline points in the source record.
p. 47 and Fig. 9’s caption: ‘Ar-Ar rates of 8, 38 and 12 MHz/Torr’ for 801.699, 800.836 and 795.036 nm, from the linear fit gamma = gamma_Ar f_Ar + gamma_He (1 - f_Ar) to the mixtures’ broadening rates (Table 1, 2.5-25 % Ar); the authors’ ‘estimate’, no uncertainty; an extrapolation to pure argon. Use check (record notes). One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
eshel_2016/broadening_He_fit#
{
"id": "broadening_He_fit",
"material": "Ar",
"table": "text",
"quantity": "pressure_line_coefficient",
"unit": "MHz/torr",
"abscissa": "label",
"use": "check",
"uncertainty": {
"level": "not stated"
},
"parameters": {
"effect": "broadening",
"transition": "the rows: 801.699 nm (s5 -> p8), 800.836 nm (s4 -> p6), 795.036 nm (s3 -> p4), vacuum wavelengths",
"photons": 1,
"frequency_scale": "transition",
"width": "fwhm",
"frequency_variable": "ordinary",
"perturber": "He",
"temperature_k": 440,
"pressure_range": "10-160 Torr (mixtures of 2.5-25 % Ar)",
"method": "linear fit of the mixtures' broadening rates against the Ar fraction (Ar-He part)"
}
}
3 inline points in the source record.
p. 47 and Fig. 9’s caption: ‘Ar-He rates of 16, 16 and 19 MHz/Torr’ for 801.699, 800.836 and 795.036 nm, from the linear fit gamma = gamma_Ar f_Ar + gamma_He (1 - f_Ar) to the mixtures’ broadening rates (Table 1, 2.5-25 % Ar); the authors’ ‘estimate’, no uncertainty; an extrapolation to pure helium. Use check (record notes). One-photon 4s-4p lines, not the ground-to-4p two-photon coherence.
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.