Quantum Molar Density and Quantum Pascal

Refractometry constitutes an optical technique for assessment of refractivity, n-1, that also can assess molar density and gas pressure with high precision and accuracy.

It has been anticipated that it could be used for assessment of pressure with a huge dynamic range, 1 mPa - 10 Pa, and with a precision and accuracy of 1 and 10 ppm, respectively. However, this is far beyond what any existing instrumentation can achieve today. The reason is that conventional refractometry suffers from a number of limitations caused by fluctuations and drifts.

To remedy this, we have developed a novel laser-based methodology, GAs MOdulation Refractometry (GAMOR), that can alleviate such limitations.

It will be further developed so as to allow for the realization of instrumentation that can reach the aforementioned goals.

To make this possible, novel modulation and characterization procedures will be developed that will eliminate the influence of pressure-induced cavity deformation that often is the limiting factor in conventional refractometry.

This will allow for assessments solely limited by the accuracy of the molar polarizabilities of two gases (He and N2), which typically are in the low ppm range.

This would make the systems calibration-free, which will open up for a number of applications, including serving as primary standards for both molar density and pressure, i.e. so as to realize both the “mol per cubic meter” (“Quantum Molar Density”) and the “Pascal” (“Quantum Pascal”) entities.