Realization of the pascal based on argon using a Fabry-Perot refractometer

Area of Science:

• Metrology and Quantum Optics
• Gas Phase Physics and Chemistry

Background:

• Accurate realization of the SI unit of pressure is crucial for scientific and industrial applications.
• Gas polarizability measurements provide fundamental data for understanding molecular properties and interactions.

Purpose of the Study:

• To realize the SI unit of pressure (pascal) up to 100 kPa using argon polarizability.
• To determine the molar polarizability of nitrogen (N2) at a specific wavelength and temperature.

Main Methods:

• Utilized a Fabry-Perot refractometer operating at 1550 nm.
• Combined experimental static polarizability of argon with first-principle calculations of frequency-dependent dipole polarizability.
• Performed measurements at a temperature of 302.9146 K.

Main Results:

• Achieved a realization of the pascal up to 100 kPa with a combined uncertainty.
• Determined the molar polarizability of N2 at 1550 nm and 302.9146 K to be 4.396572(26) × 10^-6 m^3/mol.
• The obtained N2 molar polarizability value shows good agreement with previous determinations.

Conclusions:

• The study demonstrates a novel method for pressure realization based on gas polarizability.
• The precise molar polarizability of N2 contributes valuable data to the field of molecular spectroscopy and gas phase physics.