title: Second-order quadrupole interaction based detection of ultra-slow motions: Tensor operator framework for central-transition spectroscopy and the dynamics in hexagonal ice as an experimental example.
abstract: The second-order quadrupolar broadening of the central transition of nuclear probes with half-integer spins I is demonstrated to be useful to detect ultraslow molecular motions. On the basis of density matrix calculations explicit expressions are derived for quadrupolarly modulated sin-sin and cos-cos signals of selectively excited nuclei with I=3/2, 5/2, 7/2, and 9/2. These correlation functions are suitable for implementation in two-dimensional exchange spectroscopy as well as for stimulated-echo experiments. As an application,17O measurements of the reorientational correlation function of water molecules in hexagonal ice are presented.
authors.affiliation: Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
authors.forename: Mischa
authors.initials: M
authors.lastname: Adjei-Acheamfour
authors.affiliation: Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Böhmer
keywords: Central line; Oxygen-17; Second-order quadrupole coupling; Stimulated-echo