title: 1H NMR at Larmor frequencies down to 3Hz by means of Field-Cycling techniques.
abstract: Field-Cycling (FC) NMR experiments were carried out at1H Larmor frequencies down to about 3Hz. This could be achieved by fast switching a high polarizing magnetic field down to a low evolution field which is tilted with respect to the polarization field. Then, the low frequency Larmor precession of the nuclear spin magnetization about this evolution field is registered by means of FIDs in a high detection field. The crucial technical point of the experiment is the stabilization of the evolution field, which is achieved by compensating for temporal magnetic field fluctuations of all three spatial components. The paper reports on some other basic low field experiments such as the simultaneous measurement of the Larmor frequency and the spin-lattice relaxation time in such small fields as well as the irradiation of oscillating transversal magnetic field pulses at very low frequencies as a novel method for field calibration in low field FC NMR. The potential of low field FC is exemplified by the1H relaxation dispersion of water at frequencies below about 2kHz stemming from the slow proton exchange process.
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany. Electronic address: benjamin.kresse@physik.tu-darmstadt.de.
authors.forename: B
authors.initials: B
authors.lastname: Kresse
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Becher
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
authors.forename: A F
authors.initials: AF
authors.lastname: Privalov
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: M
authors.initials: M
authors.lastname: Hofmann
authors.affiliation: Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany.
authors.forename: E A
authors.initials: EA
authors.lastname: Rössler
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Vogel
authors.affiliation: Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Fujara
keywords: FC NMR; Low field; Magnetic field calibration; Proton exchange; Relaxometry; Small Larmor frequencies