title: Exploring the limits of polarization transfer efficiency in homonuclear three spin systems.
abstract: The limits of polarization transfer efficiency are explored for systems consisting of three isotropically coupled spins 1/2 in the absence of relaxation. An idealized free evolution and control Hamiltonian is studied, which provides an upper limit of transfer efficiency (in terms of transfer amplitude and transfer time) for realistic homonuclear spin systems with arbitrary Heisenberg-type coupling constants J12, J13, and J23. It is shown that optimal control based pulse sequences have significantly improved transfer efficiencies compared to conventional transfer schemes. An experimental demonstration of optimal polarization transfer is given for the case of the carbon spin system of fully 13C labelled alanine at 62.5 MHz Larmor frequency.
authors.affiliation: Chemistry Department, Technische Universität München, 85747 Garching, Germany.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Neves
authors.forename: Björn
authors.initials: B
authors.lastname: Heitmann
authors.forename: Timo O
authors.initials: TO
authors.lastname: Reiss
authors.forename: Heloiza H R
authors.initials: HH
authors.lastname: Schor
authors.forename: Navin
authors.initials: N
authors.lastname: Khaneja
authors.forename: Steffen J
authors.initials: SJ
authors.lastname: Glaser
mesh_terms: D000409:Alanine / Q000737:chemistry*; D000465:Algorithms; D002247:Carbon Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*
chemical_list: D002247:Carbon Isotopes; D000409:Alanine