Changes

This concept is quite important for understanding relaxation in NMR or, in fact, any rotational process in physics. It is important for understanding the model-free equations, for reduced spectral density mapping, for SRLS, and for relaxation dispersion. The reason is because R1 and R2 are measured in rad/s. As I describe described in section 1[[#SI supplementary units]], the radian unit can be dropped because it is plainly obvious that NMR and relaxation is an angular process and hence radian units are implied (that was sarcastic). Hence R2 can be said to be in units of 1/s, but never, ever Hz. Also note that because of the SI conventions described below, describing the correlation time in s units does not prove that there are no radian units. But reporting rates as Hz implies no radian units whereas reporting as 1/s instead often means radian units are present.