title: New line-narrowing effect in triple-quantum resonance in a two-level NMR system.
abstract: We report a new line-narrowing effect associated with triple-quantum resonance in a two-level NMR system. The experiment was carried out in the rotating frame on (19)F nuclei in Teflon; namely, the magnetization is spin-locked along the RF field and the triple-quantum resonance is induced by the oscillating field perpendicular to the RF field. We observed that the decay time of the triple-quantum nutation becomes extraordinarily long at a particular intensity and frequency of the oscillating field. The decay time is about seven times as long as that of the single-quantum nutation and also much longer than that of the magic angle nutation. The mechanism is not interpreted by straightforward analogy to the theory of the current magic angle narrowing.
authors.affiliation: Department of Physics, Faculty of Education, Kanazawa University, Kanazawa 920-1192, Japan. hatanaka@ed.kanazawa-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hatanaka
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tabuchi