This article builds upon a previous work dealing with the budget of uncertainties associated to our recent determination of the Boltzmann constant by means of Doppler broadening thermometry. We report on the outcomes of theoretical calculations and numerical simulations aimed to precisely quantify the influence of the unresolved hyperfine structure of a given ortho component of the H218O spectrum at 1.4 μm on the measurement of the Doppler width of the line itself. We have found that, if the hyperfine structure 44,1 → 44,0 of the line of the ν1ν3 band was ignored, the spectroscopic measurement of the Boltzmann constant would be affected by a relative systematical deviation of 4·10-8.
Hyperfine structure effects in Doppler-broadening thermometry on water vapor at 1.4 μm
GIANFRANI, Livio
2016
Abstract
This article builds upon a previous work dealing with the budget of uncertainties associated to our recent determination of the Boltzmann constant by means of Doppler broadening thermometry. We report on the outcomes of theoretical calculations and numerical simulations aimed to precisely quantify the influence of the unresolved hyperfine structure of a given ortho component of the H218O spectrum at 1.4 μm on the measurement of the Doppler width of the line itself. We have found that, if the hyperfine structure 44,1 → 44,0 of the line of the ν1ν3 band was ignored, the spectroscopic measurement of the Boltzmann constant would be affected by a relative systematical deviation of 4·10-8.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
