Broadband adiabatic inversion experiments for the measurement of longitudinal relaxation time constants

Accurate measurements of longitudinal relaxation time constants (T1) in solid-state nuclear magnetic resonance (SSNMR) experiments are important for the study molecular-level structure and dynamics. Such often made under magic-angle spinning conditions; however, there numerous instances where they must be on stationary samples, which give rise to broad powder patterns arising from large anisotropic NMR interactions. In this work, we explore use wideband uniform-rate smooth-truncation pulses measurement T1 constants. Two introduced: (i) BRAIN-CPT1, a modification BRAIN-CP (BRoadband Adiabatic-INversion-Cross Polarization) sequence, broadband CP-based (ii) WCPMG-IR, WURST-CPMG direct-excitation (DE) inversion-recovery experiments. A series measured spin-1/2 quadrupolar nuclei with patterns, such as 119Sn (I = 1/2), 35Cl 3/2), 2H 1), 195Pt 1/2). High signal-to-noise spectra uniform can obtained due signal enhancements T2eff-weighted echo trains, favorable cases, BRAIN-CPT1 allows rapid comparison DE Protocols spectral acquisition, processing, analysis data discussed. most behavior modeled either monoexponential or biexponential functions based upon integrated pattern intensity; it is also demonstrated that one interpret values caution, by anisotropy 119Sn, 2H, spectra.