Rotational correlation time () is the average time it takes for a
molecule to rotate one
radian.[citation needed] In solution, rotational correlation times are in the order of
picoseconds. For example, the 1.7 ps for water,[1] and 100 ps for a pyrroline nitroxyl radical in a DMSO-water mixture.[2] Rotational correlation times are employed in the measurement of
microviscosity (viscosity at the molecular level) and in protein characterization.
^Lankhorst, D.; Schriever, J.; Leyte, J. C. (March 1982). "Determination of the Rotational Correlation Time of Water by Proton NMR Relaxation in H217O and Some Related Results". Berichte der Bunsengesellschaft für physikalische Chemie. 86 (3): 215–221.
doi:
10.1002/bbpc.19820860308.