Measurements Of Transverse Relaxation Rates Research Articles

Measurement of transverse relaxation rates for individual protons in first-order spin-coupled NMR spectra

Measurement of transverse relaxation rates for individual protons in first-order spin-coupled NMR spectra

On the Measurement of Transverse Relaxation Rates in Complex Spin Systems

Selective measurement of transverse relaxation rates of each line in a complex NMR spectrum can be accomplished by subjecting the spin system to a nonselective Carr-Purcell sequence of rf pulses, Fourier transforming the free precession following the last echo maximum, and repeating the experiment for several different durations of the echo train. Effects of homonuclear spin coupling on such measurements are exmined in detail. It is shown that such coupling can produce severe distortion of the apparent time decay of partially relaxed spectral lines. Criteria for avoiding the distortion are established, and a general scheme for interpreting selectively measured transverse relaxation rates in the framework of Redfield theory is proposed.