Experimental benchmark value for the molar polarizability of neon

With dielectric-constant gas thermometry (DCGT), the molar polarizability of neon has been determined with a relative standard uncertainty of about 11 parts in 10 6 (11 ppm). A series of isotherms using helium and neon as measuring gas have been taken and the ab initio value for the polarizability of helium has been used to achieve this unprecedented level of uncertainty. The result of A DCGT Ne =9.94727×10 −7 m 3 /mol agrees with the latest theoretical calculation on the level of a few parts in 10 4 , but shows a relative deviation from the existing (experimental) reference value of several parts in 10 3 .