title: Study of cross - relaxation and molecular dynamics in the solid 3-(trifluoromethyl) benzoic acid by solid state NMR off - resonance.
abstract: Molecular dynamics of the solid 3-(trifluoromethyl) benzoic acid containing proton1H and fluorine19F nuclei was explored by the solid-state NMR off - resonance technique. Contrary to the previous experiments the proton nuclei system I relaxed in the off - resonance effective field B→ewhile fluorine nuclei system S was saturated for short time in comparison to the relaxation time T1I. New cross - relaxation solid - state NMR off - resonance experiments were conducted on a homebuilt pulse spectrometer operating at the on-resonance frequency of 30.2MHz, at the off - resonance frequency varied between 30.2 and 30.6MHz for protons and at the frequency of 28.411MHz for fluorines, respectively. Based on the experimental data the dispersions of the proton off - resonance spin - lattice relaxation rate ρρI, the fluorine off - resonance spin - lattice relaxation rate ρρSand the cross - relaxation rate σρin the rotating frame were determined.
authors.affiliation: High Pressure Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland. Electronic address: abraszak@amu.edu.pl.
authors.forename: Aneta
authors.initials: A
authors.lastname: Woźniak-Braszak
keywords: Cross-relaxation; Heteronuclear interactions; Solid - state NMR off-resonance