%0 Journal Article %1 kuethe2005inert %A Kuethe, Dean O. %A Pietraß, Tanja %A Behr, Volker C. %D 2005 %J J Magn Reson %K mri %N 2 %P 212-220 %R 10.1016/j.jmr.2005.07.022 %T Inert fluorinated gas T1 calculator %V 177 %X The physics of spin–rotation interaction in roughly spherical perfluorinated gas molecules has been studied extensively. But, it is difficult to calculate a spin–lattice relaxation time constant T1 for any given temperature and pressure using the published literature. We give a unified parameterization that makes use of the Clausius equation of state, Lennard-Jones collision dynamics, and a formulaic temperature dependence for collision cross section for rotational change. The model fits T1s for SF6, CF4, C2F6, and c-C4F8 for temperatures from 180 to 360 K and pressures from 2 to 210 kPa and in mixtures with other common gases to within our limits of measurement. It also fits previous data tabulated according to known number densities. Given a pressure, temperature, and mixture composition, one can now calculate T1s for common laboratory conditions with a known accuracy, typically 0.5%. Given the success of the model’s formulaic structure, it is likely to apply to even broader ranges of physical conditions and to other gases that relax by spin–rotation interaction.

@article{kuethe2005inert, abstract = {The physics of spin–rotation interaction in roughly spherical perfluorinated gas molecules has been studied extensively. But, it is difficult to calculate a spin–lattice relaxation time constant T1 for any given temperature and pressure using the published literature. We give a unified parameterization that makes use of the Clausius equation of state, Lennard-Jones collision dynamics, and a formulaic temperature dependence for collision cross section for rotational change. The model fits T1s for SF6, CF4, C2F6, and c-C4F8 for temperatures from 180 to 360 K and pressures from 2 to 210 kPa and in mixtures with other common gases to within our limits of measurement. It also fits previous data tabulated according to known number densities. Given a pressure, temperature, and mixture composition, one can now calculate T1s for common laboratory conditions with a known accuracy, typically 0.5%. Given the success of the model’s formulaic structure, it is likely to apply to even broader ranges of physical conditions and to other gases that relax by spin–rotation interaction.}, added-at = {2020-03-30T13:48:15.000+0200}, author = {Kuethe, Dean O. and Pietraß, Tanja and Behr, Volker C.}, biburl = {https://www.bibsonomy.org/bibtex/25cbc740d4d55b0024312c951a6d1fd0f/ep5mri}, doi = {10.1016/j.jmr.2005.07.022}, interhash = {9ed629d701913655b9491d90991d85e7}, intrahash = {5cbc740d4d55b0024312c951a6d1fd0f}, journal = {J Magn Reson}, keywords = {mri}, month = {12}, number = 2, pages = {212-220}, timestamp = {2020-04-01T15:44:11.000+0200}, title = {Inert fluorinated gas T1 calculator}, volume = 177, year = 2005 }