Measurement of transverse relaxation using spin echo methods

Title: Measurement of transverse relaxation using spin echo methods Author: MUDr. Antonin Skoch, Ph.D. Department: Department of Low Temperature Physics Supervisor: RNDr. Zdenek ToSner, Ph.D. NMR laboratory, of Faculty of science, Charles University in Prague Supervisor's e-mail address: tosner(o)karlov.mff.cuni.cz Abstract: The study of TI relaxation in systems with homonuclear J-coupling is complicated by modulation in the relaxation curve. This J-modulation can be removed when CPMG sequence is used and the period of repetition of refocusing pulse Tfulfils a condition r « * ( 1 ) Ai' where Av is the frequency difference of coupled nuclei. However, the condition (I) cannot be in practice always fulfilled. The aim of this work was to investigate J-modulation and relaxation behaviour of homonuclear J-coupled system in various parameters of CPMG sequence. Simulations based on numerical solution of Liouville-von Neumann equation and Redfield theory were performed. Relaxation curves of Chh group of citrate were measured on high-resolution NMR spectrometer. It was found that the suppression of J-modulation can be achieved also for T longer than required by the condition (1) providing that the refocusing angle in CPMG for both J-coupling partners 9^180ř. The simulations yielded conditions for T when J-modulation...