Inert fluorinated gas T1 calculator.

Area of Science:

• Physical Chemistry
• Chemical Physics
• Molecular Spectroscopy

Background:

• Spin-rotation interaction is crucial for understanding relaxation dynamics in gases.
• Calculating spin-lattice relaxation time (T1) constants for perfluorinated molecules is complex using existing literature.
• Previous models lacked a unified approach for predicting T1 under diverse conditions.

Purpose of the Study:

• To develop a unified parameterization for calculating spin-lattice relaxation time (T1) constants.
• To provide accurate T1 predictions for spherical perfluorinated gases at various temperatures and pressures.
• To establish a reliable method for T1 calculation in gas mixtures.

Main Methods:

• Utilized the Clausius equation of state for thermodynamic properties.
• Incorporated Lennard-Jones collision dynamics to model molecular interactions.
• Developed a formulaic temperature dependence for collision cross-sections affecting rotational changes.

Main Results:

• The model accurately fits T1 data for SF6, CF4, C2F6, and c-C4F8 from 180-360 K and 2-210 kPa.
• Predictions align with experimental measurements and previously tabulated data within typical 0.5% accuracy.
• Successfully modeled T1 in mixtures with common gases.

Conclusions:

• The unified parameterization offers a robust method for calculating T1 for spherical perfluorinated gases.
• The model's success suggests applicability to wider physical conditions and other spin-rotation relaxing gases.
• Enables precise T1 calculations for common laboratory conditions based on pressure, temperature, and mixture composition.