Detection of the extremely weak S(8) line of D2. Upper panel: CRDS spectrum of D2 recorded at 700 Torr. The v = 2–0 S(8) line of D2 is located in the far wing of a line of water present as an impurity in the CRDS cell. The dots correspond to the measurements while the solid line is the line profile simulation obtained with a Galatry profile for D2 and a Voigt profile for H2O. Lower panel: Residuals between the experimental and simulated spectra. The rms of the residuals is close to the noise equivalent absorption (α min ≈ 4 × 10−12 cm−1).
Comparison of the profile of the v = 2–0 S(8) line of D2 recorded at 100 and 500 Torr (solid and dot lines, respectively) showing the Dicke narrowing effect and the pressure induced line shift. The absorption coefficient at maximum has been normalised to 1 for the clarity of the comparison.
Line profile simulation of the v = 2–0 S(6) and S(4) lines of D2 recorded at 500 Torr and 750 Torr, respectively. Upper panels: Experimental spectrum (dots) and profile simulation using a Galatry profile (red line). Lower panels: Residuals between the experimental and simulated spectra for the Voigt, and Galatry profiles. Note the different scale used for the residuals.
Line intensity and pressure shift retrievals for the v = 2–0 S(4) transition of D2. Upper panel: Variation of the line centre versus the pressure and corresponding linear fit; Lower panel: Variation of the integrated absorption coefficient at 296K obtained with a Galatry profile fit versus the pressure. The straight lines correspond to the best linear fit.
Overview of the calculated spectrum of D2 at 296 K between 0 and 24 000 cm−1. Note that a number of hot band transitions contribute to the spectrum below 7000 cm−1.
Overview of the calculated spectrum of D2 at 296 K. The D2 transitions reported in the literature with intensity values14,15 are highlighted (open circles blue) together with the present CRDS measurements (full circles red).
Intensity ratio at 296 K for the (2–0) transitions versus the calculated intensity values. The squares and stars correspond to the CRDS (this work) and ICOS (Ref. 14) measurements, respectively. The error bars are those given in Ref. 14 for the ICOS measurements while a constant value of 2% is adopted for the strongest CRDS values, mostly related to the choice of the line profile function (see text). The uncertainty on the temperature value (296 ± 1 K) contributes slightly to the uncertainty on the CRDS intensities of the S(4)-S(6) lines.
Centre, intensity, and pressure shift coefficient for the transitions of the (1–0) and (2–0) bands of D2. Literature values are given in italics.
Calculated values of the position, transition moment, Einstein coefficient, lower state energy population factor, and line intensity at 296 K for the (0–0), (1–0), and (2–0) transitions of D2 with intensities larger than 1 × 10−30 cm/molecule. This table is a sample of the whole calculated line list, provided as supplementary material, for pure D2 up to 24 000 cm−1 (intensity cutoff of 1 × 10−34 cm/molecule).
Rovibrational parameters of the v = 0–19 vibrational levels of D2 obtained from the fit of the J = 0–7 energy levels calculated in Ref. 21. Note: The uncertainties are given in parenthesis in the unit of the last quoted digit. They correspond to the statistical error of the fit and do not take into account the error bar on the calculated value of the energy levels.
Article metrics loading...
Full text loading...