Accurate deuterium spectroscopy and comparison with ab initio calculations

Abstract

We present accurate measurements of the quadrupole S(3) and S(4) transitions of the D2 2 − 0 band. Self-perturbed spectra were collected in a wide pressure range with a cavity ring-down spectrometer linked to an optical frequency comb. The results of ab initio quantum scattering calculations were incorporated into the line-shape analysis which was performed using the Hartmann-Tran profile. This approach allowed us to mitigate the collisional systematics and to reach a 900 kHz accuracy of the transition frequencies, which represents a 30-fold improvement compared to previously available data. We also compare our findings with newly calculated transition frequencies that include relativistic and QED corrections up to α 7. The differences between theoretical and experimental values for the transition frequencies are 2.2 MHz and 3.3 MHz for the S(3) and S(4) transitions, respectively.

Hyperfine components of all rovibrational quadrupole transitions in the H$_{2}$ and D$_{2}$ molecules

“…Nevertheless, the best measurements for the D 2 molecule, performed for the S(2) line from the first overtone, reached the accuracies of 500 kHz [16], 400 kHz [20] and even 161 kHz [23]. The first overtone in D 2 was also recently studied by Wójtewicz et al [24], who reported 870 and 999 kHz combined uncertainties for the positions of the S(3) and S(4) lines, respectively. Mondelain et al [25], estimated the uncertainty of the frequencies of the S(0) and Q(1)-Q(4) D 2 transitions between 0.3 and 1.83 MHz.…”

“…Theoretical studies of the rovibrational structure of the ground electronic state in molecular hydrogen achieve remarkable accuracy in the determined dissociation energy [1][2][3][4][5] and rovibrational energy levels [6][7][8][9][10][11][12]. The progress in the theoretical investigations is enhanced by recent experiments, which aim at the sub-MHz accuracy of both the dissociation energy [13,14] and the rovibrational transition frequencies in the ground electronic state [15][16][17][18][19][20][21][22][23][24][25][26][27]. Comparison between theoretical calculations and accurate measurements can be used as a test for the quantum electrodynamics for molecules [12], determination of the proton-charge radius [1,8,13,14] or even searches for physics beyond Standard Model [28], i.e.…”

Cavity Ring-Down Spectroscopy: Recent Technological Advancements, Techniques, and Applications

“…The FARS-CRDS is mostly used in conjunction with OFCs to take full advantage of both the methods for precision spectroscopy. − For instance, high-resolution spectra of simple molecules such as D 2 which can help to correctly predict physical models have been probed by these techniques. Recently, an optical cavity with a staggering finesse of 6.37 × 10 5 was employed with FARS to probe the weak quadrupole line S(2) in the 2–0 band of D 2 around ∼1.6 μm with an average noise of 8 × 10 –12 cm –1 .…”

“…Recently, an optical cavity with a staggering finesse of 6.37 × 10 5 was employed with FARS to probe the weak quadrupole line S(2) in the 2–0 band of D 2 around ∼1.6 μm with an average noise of 8 × 10 –12 cm –1 . In a similar study, the S(3) and S(4) lines of D 2 , near the ∼1.56 μm region, in the same band were analyzed at high pressures (100–900 Torr). Careful line shape analysis was carried out through quantum scattering calculations to improve accuracy and test QED corrections.…”

A Theoretical Study on Vibrational Energies of Molecular Hydrogen and Its Isotopes Using a Semi-classical Approximation

“…Exact experimental vibrational levels for H2 and deuterium-bearing hydrogen molecules, i.e., hydrogen deuteride (HD) and dideuterium (D2) have been widely reported in the literature [3][4][5]. On the other hand, physical properties of the tritium-bearing hydrogen molecules, i.e., tritiated hydrogen (HT), deuterium-tritium (DT), and ditritium (T2), have been less frequently measured.…”