Absolute frequency determination of molecular transition in the Doppler regime at kHz level of accuracy

Abstract

We measured absolute frequency of the unperturbed P7 P7 O2 B-band transition ν0 = 434783.5084857(82) GHz and the collisional self-shift coefficient δ = −9.381(62) × 10 −21 GHz/(molecule/cm 3 ). With Doppler-limited spectroscopy we achieved the relative standard uncertainty of 2 × 10 −11 on line position, typical for Doppler-free techniques. Shapes of the spectral line were measured with a Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer referenced to an 88 Sr optical atomic clock via an optical frequency comb.

Precision spectra of AΣ+2 , v′=0

“…The results presented in this work are precise Dopplerbroadened measurements of molecular electronic transitions, comparable in relative precision to the recent measurements of the P7 P7 B-band transition in O 2 by Bielska and co-workers [26]. By measuring all experimentally accessible transitions from the rovibronic ground state, we have also been able to determine the A-state spectroscopic constants, particularly the band origin and rotational constants, with far higher precision than in previous measurements.…”

Comb coherence-transfer and cavity ring-down saturation spectroscopy around 1.65 μm: kHz-accurate frequencies of transitions in the 2ν3 band of 12CH4

“…At low pressures, when collision broadening is negligible, Doppler broadening is usually the limiting factor, leading to a typical room temperature linewidth of hundreds of MHz in the near-IR and visible ranges for most small polyatomic molecules. While line centers have been determined with uncertainty below dn o 10 kHz for isolated spectral lines, [3][4][5] the situation is much worse in cases when multiple spectral lines are overlapping within their Doppler widths, necessitating multiline fits. Line uncertainties of tens of MHz are common in such situations.…”

Accurate deuterium spectroscopy for fundamental studies

“…The second strategy operates in the Doppler-limited regime. It takes advantage of ultra-high finesse cavities to directly measure Email address: piotr.wcislo@fizyka.umk.pl (P. Wcisło) the weak quadrupole lines and has already achieved the kilohertz level of accuracy [10][11][12] typical for Doppler-free techniques. However, in the case of molecular hydrogen, the collisional line-shape effects are very pronounced and untypical [13][14][15].…”