Time between the inversion pulse and the sampling pulse(s) in an
inversion recovery sequence.
Note:
\(T_{\rm{I,null}}\) is the value of \(T_{\rm{I}}\) when longitudinal magnetization (\(M_{\rm{z}}\)) is close to zero at the end of the \(\ce{TI}\) interval.
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 694 (https://doi.org/10.1515/pac-2019-0203)