rosasco_1983#
G. J. Rosasco, W. Lempert, W. S. Hurst and A. Fein, “Line interference effects in the vibrational Q-branch spectra of N2 and CO”, Chem. Phys. Lett. 97, 435 (1983)
Source record · Catalogue · Review register
DOI: 10.1016/0009-2614(83)80524-7
Source kind: measurement
Recorded technique: High-resolution cw stimulated Raman (Raman loss) spectroscopy (p. 435): a single-mode Kr-ion pump (< 20 MHz) and a tunable ring-dye probe (about 1 MHz), copropagating, parallel linear polarisations, pump modulated at 5.4 MHz, multipass cell (about 50-fold); frequency precision about 30 MHz (0.001 cm-1) over a Q branch. Pure N2 and pure CO, v = 0 -> 1 Q branches, self-broadened, about 20-200 kPa (0.2-2.0 atm), 298 K. Line overlap described by a relaxation-matrix model; the first-order (in density) solution, Eq. (6), fitted to spectra at 0.2 and 0.6 atm (N2) and 0.2 and 0.5 atm (CO) gives gamma_j and Y_j (p. 437).
Materials in structured entries: CO, N2
Dataset quantities: raman_linewidth
Contents: 2 datasets; 2 formulas.
Curation notes#
Identity checked against the first page. Page numbers are journal pages (pdf pages 1-6 = pp. 435-440). Materials: 14N2 and 12C16O (natural gases); no other isotopologue.
WIDTH CONVENTION. HALF widths. The paper never writes ‘HWHM’ against Table 1; the convention follows from Eq. (6) (p. 436): chi3’’(omega) = (n/24 hbar) sum_j alpha_j^2 Delta rho_0j p [gamma_j - (omega - omega_j) Y_j] / [(omega - omega_j)^2 + (p gamma_j)^2], ‘with ... p the pressure, gamma_j = W_jj the line-broadening coefficient’. A Lorentzian gamma/(x^2 + (p gamma)^2) has its half width at half maximum at x = p gamma: p gamma_j is the HWHM, and gamma_j the HWHM per atm. Independent confirmation: Rahn and Palmer (rahn_1986, Table 1, ‘FWHM’, note a ‘From Ref. 6’ = this paper) print exactly twice these values and errors for N2 (all 19 rows), and Farrow and Rahn (farrow_1985) label their comparable Ar coefficients ‘HWHM’. Per atm of pressure at 298 K (‘Line-broadening and mixing-coefficients at 298 K’, Table 1 caption, p. 438), not per amagat. The isolated-line study behind the method (Ref. 6, Spectral Line Shapes Vol. 2, not in the library): Voigt at 0.05 atm, Dicke narrowing with rising pressure, Lorentzian above 0.2 atm; ‘The collision component Gamma(p) is extracted using the known Doppler (about 80 MHz) and diffusion (about 6 MHz at 1.0 atm) contributions’, and Gamma(p) = p gamma holds to 2.0 atm (p. 437).
UNCERTAINTIES. gamma_j: the parenthesised digits (last decimal) are not described (level not stated). Y_j: the table’s notes, poorly printed, read ‘a) +-20 %, J = 0-3’ and ‘b) +-50 %, J = 4-18’ (the ‘a’ note’s ‘+-20 %’ is inferred from the partly legible scan, ‘-20 .,’, and the legible ‘b) +-50 %’), marked on J = 0 and J = 4 of each column.
THE LINE-MIXING COEFFICIENTS Y_j (atm-1) have no quantity in the vocabulary. They are recorded as the coefficients of Eq. (6) in the formulas eq6_N2 and eq6_CO. Definition, Eq. (7) (p. 436): Y_j = 2 sum_{j’ != j} (alpha_j’/alpha_j) W_j’j / (omega_j’ - omega_j), W the relaxation matrix (Eq. (5)); ‘first order in density’; all alpha_j equal in the paper’s normalisation. Eq. (6) with Table 1 ‘yields good agreement with the data up to 2.0 atm’ (p. 437).
TEXT VALUES (notes only). N2 line shifts ‘less than 0.001 cm-1 atm-1’ (Ref. 6); CO Q(14) shift about 0.0045(9) cm-1 atm-1 (sign not printed); CO B1 - B0 from -0.017511(6) cm-1 (0.2 atm) to -0.017495(8) cm-1 (1.0 atm) (p. 438). Fitting the pure Lorentzian model with free T gives temperatures ‘about 40 K too low’ at 1 atm (p. 437). Eq. (8) (p. 438), the state-to-state rate law used to model gamma_j and Y_j (power law about 0.5 with N_x = N_c at low j, exponential gap with N_0 at high j; results in Fig. 3 for CO only): no fitted constants are printed.
What this bears on: the N2 Q-branch self-broadening at room temperature (the N2 Q widths in use, TC-492) and line mixing, which is not yet modelled (docs/raman.md, ‘Line mixing’). This is the source of Rahn and Palmer’s 295 K column and of Farrow and Rahn’s self-broadening correction (farrow_1985).
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
rosasco_1983/table1_N2#
{
"id": "table1_N2",
"material": "N2",
"file": "N2/rosasco_1983__table1_N2.csv",
"table": "tbl_ee3e296d7c2c",
"quantity": "raman_linewidth",
"unit": "cm-1/atm",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"transition": "Q(J), v = 0 -> 1, per row",
"width": "hwhm",
"perturber": "self",
"temperature_k": 298
}
}
Table 1 (p. 438), N2 column gamma_j: HWHM self-broadening coefficient of the Q(J) lines (v = 0 -> 1), cm-1 per atm, 298 K, J = 0-18 (HWHM from Eq. (6): see the source notes). Fitted with Eq. (6) (line mixing included) to 0.2 and 0.6 atm spectra. Error in the last digits, level not stated. rahn_1986 prints these doubled as its 295 K FWHM column.
rosasco_1983/table1_CO#
{
"id": "table1_CO",
"material": "CO",
"file": "CO/rosasco_1983__table1_CO.csv",
"table": "tbl_ee3e296d7c2c",
"quantity": "raman_linewidth",
"unit": "cm-1/atm",
"abscissa": "label",
"use": "primary",
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"transition": "Q(J), v = 0 -> 1, per row",
"width": "hwhm",
"perturber": "self",
"temperature_k": 298
}
}
Table 1 (p. 438), CO column gamma_j: HWHM self-broadening coefficient of the Q(J) lines (v = 0 -> 1), cm-1 per atm, 298 K, J = 0-18 (HWHM from Eq. (6): see the source notes). Fitted with Eq. (6) to 0.2 and 0.5 atm spectra. Error in the last digits, level not stated. ‘in excellent agreement with the recently reported [32] widths of P- and R-branch lines in the infrared vibrational overtone spectrum’ (p. 438).
Formulas#
rosasco_1983/eq6_N2#
{
"id": "eq6_N2",
"material": "N2",
"equation": "Eqs. (6)-(7), p. 436; Table 1 (tbl_ee3e296d7c2c), p. 438",
"printed": "chi3''(omega) = (n/24 hbar) sum_j alpha_j^2 Delta rho_0j p [gamma_j - (omega - omega_j) Y_j] / [(omega - omega_j)^2 + (p gamma_j)^2]; Y_j = 2 sum_{j' != j} (alpha_j'/alpha_j) W_j'j / (omega_j' - omega_j)",
"variable": "omega = omega_a - omega_b the Raman frequency, omega_j the Q(j) line position (in cm-1, as gamma_j); p: pressure in atm; gamma_j = W_jj the HWHM broadening coefficient in cm-1 atm-1 (dataset table1_N2); Y_j the first-order line-mixing coefficient in atm-1; n the number density; alpha_j = <v1|alpha_0|v0> (all equal); Delta rho_0j the thermal population difference of the 0 and 1 levels at J",
"state": "pure N2, 298 K",
"density": "unknown",
"range": "fitted to 0.2 and 0.6 atm; 'good agreement with the data up to 2.0 atm' (p. 437); first order in density",
"coefficients": {
"Y_Q0": "0.46",
"Y_Q1": "0.6",
"Y_Q2": "0.21",
"Y_Q3": "0.05",
"Y_Q4": "0.04",
"Y_Q5": "0.04",
"Y_Q6": "0.03",
"Y_Q7": "0.03",
"Y_Q8": "-0.03",
"Y_Q9": "0.03",
"Y_Q10": "-0.03",
"Y_Q11": "0.03",
"Y_Q12": "0.03",
"Y_Q13": "-0.03",
"Y_Q14": "0.03",
"Y_Q15": "0.03",
"Y_Q16": "0.03",
"Y_Q17": "0.03",
"Y_Q18": "0.03",
"Y_error_J0_3": "20 %",
"Y_error_J4_18": "50 %"
},
"check": "No printed spectrum value to reproduce (Figs. 1-2 are figures). Sum rule (scratch, 2026-09-27): detailed balance, rho_j W_j'j = rho_j' W_jj', makes Eq. (7) satisfy sum_j rho_j Y_j = 0 (all alpha_j equal), separately for even and odd J in N2, whose collisions conserve the nuclear-spin symmetry. With 298 K Boltzmann populations (B = 1.99 cm-1, even:odd weights 2:1) the printed Y_j give sum_j rho_j Y_j = +0.046 atm-1 against sum_j rho_j |Y_j| = 0.060 (even J +0.025, odd J +0.021): the printed N2 values do NOT satisfy the sum rule. The CO values do, nearly: -0.010 against 0.084 (B = 1.92). The N2 column is badly printed (the signs of J = 8, 10, 13 are faint dashes; image checked at 400 dpi); lost minus signs at high J are a possible cause, not established."
}
The line-mixing coefficients Y_j of Table 1’s N2 column, as printed (the marks a) and b) on J = 0 and J = 4 dropped: they are the error notes, +-20 % for J = 0-3 and +-50 % for J = 4-18). ‘No values of Q branch line-mixing coefficients have been reported in the literature’ (p. 438). Line mixing is not modelled yet (TC-492).
rosasco_1983/eq6_CO#
{
"id": "eq6_CO",
"material": "CO",
"equation": "Eqs. (6)-(7), p. 436; Table 1 (tbl_ee3e296d7c2c), p. 438",
"printed": "chi3''(omega) = (n/24 hbar) sum_j alpha_j^2 Delta rho_0j p [gamma_j - (omega - omega_j) Y_j] / [(omega - omega_j)^2 + (p gamma_j)^2]; Y_j = 2 sum_{j' != j} (alpha_j'/alpha_j) W_j'j / (omega_j' - omega_j)",
"variable": "as eq6_N2, with gamma_j the dataset table1_CO",
"state": "pure CO, 298 K",
"density": "unknown",
"range": "fitted to 0.2 and 0.5 atm; good to 2.0 atm (p. 437); first order in density",
"coefficients": {
"Y_Q0": "1.24",
"Y_Q1": "0.63",
"Y_Q2": "0.16",
"Y_Q3": "0.006",
"Y_Q4": "-0.04",
"Y_Q5": "-0.06",
"Y_Q6": "-0.06",
"Y_Q7": "-0.06",
"Y_Q8": "-0.06",
"Y_Q9": "-0.06",
"Y_Q10": "-0.06",
"Y_Q11": "-0.06",
"Y_Q12": "-0.06",
"Y_Q13": "-0.05",
"Y_Q14": "-0.05",
"Y_Q15": "-0.04",
"Y_Q16": "-0.04",
"Y_Q17": "-0.03",
"Y_Q18": "-0.03",
"Y_error_J0_3": "20 %",
"Y_error_J4_18": "50 %"
},
"check": "Sum rule as for eq6_N2 (scratch, 2026-09-27; all J mix, one sum): sum_j rho_j Y_j = -0.0097 atm-1 against sum_j rho_j |Y_j| = 0.084 at 298 K with B = 1.92 cm-1: zero to 12 % of the scale, within the stated +-20-50 %. Fig. 3b compares the Y_j with the rate-law predictions (figure only)."
}
The line-mixing coefficients Y_j of Table 1’s CO column, as printed (marks a) and b) dropped).
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.