keijser_1974#
R. A. J. Keijser, J. R. Lombardi, K. D. Van den Hout, B. C. Sanctuary and H. F. P. Knaap, “The pressure broadening of the rotational Raman lines of hydrogen isotopes”, Physica 76, 585 (1974)
Source record · Catalogue · Review register
DOI: 10.1016/0031-8914(74)90160-8
Source kind: measurement
Recorded technique: Pure rotational Raman scattering at 293 K (pp. 586-590): a single-mode argon-ion laser at 514.5 nm (600 mW), polarisation vertical to the scattering plane, 90 degree scattering from a cell at up to 125 atm; a Glan-Thompson prism passing only the depolarised component; a 25 cm monochromator (6 or 15 A slit) isolating one Stokes line, resolved by a pressure-scanned Fabry-Perot interferometer (0.198 cm spacer, free spectral range 75.6 GHz, instrumental width 1.9 GHz, finesse 40) with photon counting. The instrument deconvolved by Fourier transform, Eqs. (1)-(5); the lines are Lorentzian (ln F_R(t) linear in t), Eq. (6), and the half width is taken from the slope; the broadening coefficient Delta nu_1/2/rho from the slope of Delta nu_1/2 against density (pp. 591-594). HD at 25-75 atm, normal H2 at 75-125 atm, normal D2 at about 65-90 amagat (Fig. 13; not stated in the text); para-H2 (> 96 %) converting in the cell at 124.5 atm for the ortho-para series (p. 598). Gases: commercial H2 and D2 (purity better than 99 %); HD made from D2O and LiAlH4 (96.5 % HD, 3 % H2, 0.5 % D2).
Materials in structured entries: D2, H2
Dataset quantities: raman_linewidth
Contents: 4 datasets; 0 formulas.
Curation notes#
Identity checked against the first page. PAGES: pdf page n is journal p. 584 + n (Table I on p. 595). This is the Leiden group’s room-temperature paper (Communication No. 408c); knaap_1979 (Phil. Trans. 1979) extends the same measurements to 25-300 K in figures only, and van_den_hout_1980 gives the low-temperature tables.
MATERIALS. Normal H2 (‘3/4 ortho (odd j) and 1/4 para (even j)’) and normal D2 (‘2/3 ortho (even j) and 1/3 para (odd j)’), p. 596. HD is not a material: its values are in these notes. Only the Stokes lines S_o(J) (J -> J + 2, v = 0) were measured.
WIDTH CONVENTION: HALF WIDTHS. Eq. (6), p. 592: F_R(t) = exp(-2 pi Delta nu_1/2 t), ‘where Delta nu_1/2 is the half-width (half the width at half intensity) of the associated lorentzian line profile’ (p. 593), R(nu) = (I_0/pi) Delta nu_1/2 / (nu^2 + Delta nu_1/2^2), Eq. (7). The appendix repeats it: ‘The half-width (at half intensity) for the S_o(j) Raman lines’ (p. 605). Table I: ‘Delta nu_1/2/rho in GHz/amagat’ (p. 595), a frequency (not angular); ‘A density of 1 amagat corresponds approximately to 2.687 x 10^19 molecules/cm3’ (the 0 C amagat). The coefficients are HWHM per amagat.
DICKE. The footnote on p. 594: ‘The translational motion of the molecules gives rise to a contribution with a different density dependence. For the hydrogen isotopes this effect has been shown to be unimportant at pressures above 25 atm’ (Refs. 16-18): all measurements are above 25 atm, and the coefficients are the slope of Delta nu_1/2 against density (no Dicke term fitted or removed; Figs. 9, 11 and 13 draw the lines through the origin).
UNCERTAINTIES. Table I prints ‘+-’ per value (0.001 GHz/amagat for H2 and D2, 0.01 for HD); the paper does not say what they are (level not stated). The ortho-para composition of each run ‘within 2 %’ (p. 590).
HD (Table I, GHz/amagat HWHM, S_o(0)-S_o(4)): 0.43, 0.38, 0.33, 0.27, 0.20, each +- 0.01; an order of magnitude above H2 and D2 (the P_1 term of the loaded-sphere potential, p. 600).
TABLE II (p. 597): fractional populations of H2 rotational levels at 293 K, j = 0-6: ortho -, 0.884, -, 0.115, -, 0.001, -; normal 0.132, 0.662, 0.115, 0.086, 0.004, 0.001, 0.000; para 0.525, -, 0.460, -, 0.015, -, 0.000.
CROSS SECTIONS (Tables III-IV, notes: no quantity). Eq. (8), p. 599: 2 pi Delta nu_1/2 = n <v>_0 S_RR, <v>_0 = (8 k_B T/pi mu)^1/2 (Eq. 9, mu the reduced mass of the pair; 2485 m/s for H2 at 293 K). Table III (A^2): HD 4.9, 4.4, 3.8, 3.1, 2.3 (+- 0.1); nH2 0.40, 0.49, 0.35, 0.36, 0.22 (+- 0.01); nD2 1.12, 0.89, 0.83, 0.68, 0.57, 0.37 (+- 0.01). Checked (scratch, 2026-09-27): Table I with n = 2.687e25 m-3 per amagat and <v>_0 = 2485 m/s x (1 amu/mu)^1/2 (mu = 1, 1.5, 2 amu for H2, HD, D2) gives 0.40 (H2 S_o(0)), 4.96 (HD S_o(0)) and 1.12 (D2 S_o(0)) A^2: Table III follows from Table I, confirming that the coefficients are per 0 C amagat and in cyclic frequency. Table IV (A^2), the extrapolated limits of Fig. 15 (Delta nu_1/2 against the para fraction at 124.5 atm, linear): pure oH2 0.36, 0.54, 0.32, 0.39, 0.22; pure pH2 0.49, 0.31, 0.43, 0.25, 0.23 (+- 0.01), S_o(0)-S_o(4). The ‘contribution of (exact) resonance collisions for some of the lines exceeds 40 % of the total linewidth’ (p. 599).
THEORY (Tables V-VI, pp. 601-604, notes only). Van Kranendonk’s quadrupole-quadrupole impact theory, Eqs. (A.1)-(A.12), extended to ortho and para perturbers: the elastic, resonance, quasi-resonance and two nonresonance parts of S_RR per line, with tau = d/v = 0.96e-13 s (Table V: total calc. oH2 0.52, 0.54, 0.52, 0.34, 0.29; pH2 0.52, 0.49, 0.39, 0.41, 0.15) and tau = 1.18e-13 s (Table VI and its continuation tbl_32991a1c3209: oH2 0.33, 0.54, 0.30, 0.34, 0.16; pH2 0.46, 0.27, 0.36, 0.21, 0.14). Table VI’s caption prints ‘tau = 1.18 x 10^-12 s’ where Figs. 19-20 and the text (‘a slightly larger value for tau (by about 20 %)’, p. 604) give 1.18 x 10^-13 s: a misprint in the caption (no data affected). The paper: the sensitivity to tau ‘indicates that a re-evaluation of the approximations in this theory is required’ (p. 604).
FIGURES (not digitised). Figs. 9, 11, 13: Delta nu_1/2 (GHz) against density (amagat) for HD, nH2, nD2; Figs. 10, 12, 14: the coefficients against J (Fig. 12 with Cooper et al. and Gupta and May); Fig. 15: the H2 widths at 124.5 atm against the para fraction 0.25-0.96; Figs. 16-17, 19-20: theory against experiment.
WHO REPRINTS IT. smyth_1987’s keijser_S_branch (the D2 row, converted to 10^-3 cm-1/ amagat, p. 1008 of that paper) and edwards_1991’s ‘Knaap et al.’ columns (Tables 7-8, which are this Table I doubled to full widths and converted to cm-1, the unit printed there as per bar) were re-pointed here on 2026-09-27 (see those records). knaap_1979 shows the same room-temperature points in its Figs. 5-6.
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
keijser_1974/table1_H2#
{
"id": "table1_H2",
"material": "H2",
"file": "H2/keijser_1974__table1_H2.csv",
"table": "tbl_ef6959254514",
"quantity": "raman_linewidth",
"unit": "GHz/amagat",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"transition": "S0(J), v = 0, J -> J + 2, per row",
"width": "hwhm",
"perturber": "self",
"temperature_k": 293,
"ortho_para": "3:1"
}
}
Table I (p. 595), nH2 ‘this exp.’: the HWHM self-broadening coefficient Delta nu_1/2/rho of the pure rotational S0(0)-S0(4) lines of normal H2 at 293 K, GHz per 0 C amagat, from 75-125 atm; no Dicke term (negligible above 25 atm, p. 594). The paper: ‘Delta nu_1/2 is the half-width (half the width at half intensity)’ (p. 593). Per-value +-0.001 (level not stated). The odd lines are broader (resonance collisions with the abundant j = 1, p. 596). In cm-1/amagat: 1.401, 1.735, 1.234, 1.268, 0.767e-3 HWHM.
keijser_1974/table1_H2_cooper#
{
"id": "table1_H2_cooper",
"material": "H2",
"file": "H2/keijser_1974__table1_H2_cooper.csv",
"table": "tbl_ef6959254514",
"quantity": "raman_linewidth",
"unit": "GHz/amagat",
"abscissa": "label",
"use": "reproduced",
"reproduced_from": [
"V. G. Cooper, A. D. May and B. K. Gupta, Can. J. Phys. 48, 725 (1970)"
],
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"transition": "S0(J), v = 0, J -> J + 2, per row",
"width": "hwhm",
"perturber": "self",
"ortho_para": "3:1"
}
}
Table I (p. 595), nH2 ‘literature’, note a (Ref. 17): S0(0) and S0(1), HWHM per amagat as the column; ‘in excellent agreement with the present results’ (p. 594). herring_1986 (Table V) prints the same paper as 84 and 105 MHz/amagat FWHM, i.e. 0.042 and 0.0525 GHz/amagat HWHM: consistent.
keijser_1974/table1_H2_gupta_may#
{
"id": "table1_H2_gupta_may",
"material": "H2",
"file": "H2/keijser_1974__table1_H2_gupta_may.csv",
"table": "tbl_ef6959254514",
"quantity": "raman_linewidth",
"unit": "GHz/amagat",
"abscissa": "label",
"use": "reproduced",
"reproduced_from": [
"B. K. Gupta and A. D. May, Can. J. Phys. 50, 1747 (1972)"
],
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"transition": "S0(J), v = 0, J -> J + 2, per row",
"width": "hwhm",
"perturber": "self",
"ortho_para": "3:1"
}
}
Table I (p. 595), nH2 ‘literature’, note b (Ref. 18): S0(1) only, HWHM per amagat as the column (split from the same cell as Ref. 17’s value; see the script).
keijser_1974/table1_D2#
{
"id": "table1_D2",
"material": "D2",
"file": "D2/keijser_1974__table1_D2.csv",
"table": "tbl_ef6959254514",
"quantity": "raman_linewidth",
"unit": "GHz/amagat",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"transition": "S0(J), v = 0, J -> J + 2, per row",
"width": "hwhm",
"perturber": "self",
"temperature_k": 293,
"ortho_para": "2:1"
}
}
Table I (p. 595), nD2: the HWHM self-broadening coefficient of the pure rotational S0(0)-S0(5) lines of normal D2 at 293 K, GHz per 0 C amagat, from about 65-90 amagat (Fig. 13); no Dicke term. Per-value +-0.001 (level not stated). The even lines are broader, the reverse of H2 (p. 596). In cm-1/amagat: 2.802, 2.235, 2.068, 1.701, 1.434, 0.934e-3 HWHM, the values smyth_1987 quotes (2.80, 2.23, 2.07, 1.70, 1.43, 0.93).
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.