%0 Journal Article
%T Accurate determination of the Boltzmann constant by Doppler spectroscopy: Towards a new definition of the kelvin
%A Beno£¿t Darqui¨¦
%A Sinda Mejri
%A Papa Lat Tabara Sow
%A Cyril Lemarchand
%A Meriam Triki
%A Sean Tokunaga
%A Christian J. Bord¨¦
%A Christian Chardonnet
%A Christophe Daussy
%J Physics
%D 2015
%I arXiv
%R 10.1051/epjconf/20135702005
%X Accurate molecular spectroscopy in the mid-infrared region allows precision measurements of fundamental constants. For instance, measuring the linewidth of an isolated Doppler-broadened absorption line of ammonia around 10 $\mu$m enables a determination of the Boltzmann constant k B. We report on our latest measurements. By fitting this lineshape to several models which include Dicke narrowing or speed-dependent collisional effects, we find that a determination of k B with an uncertainty of a few ppm is reachable. This is comparable to the best current uncertainty obtained using acoustic methods and would make a significant contribution to any new value of k B determined by the CODATA. Furthermore, having multiple independent measurements at these accuracies opens the possibility of defining the kelvin by fixing k B, an exciting prospect considering the upcoming redefinition of the International System of Units.
%U http://arxiv.org/abs/1506.06464v1