title: Relaxation selective pulses in fast relaxing systems.
abstract: In this work, the selectivity or sharpness of the saturation profiles for relaxation selective pulses (R^rsps) that suppress magnetization possessing relaxation times of T2=T2(rsp) and T1=αT2 for α∈12,∞ was optimized. Along with sharpening the selectivity of the R^rsps, the selective saturation of these pulses was also optimized to be robust to both B0 and B1 inhomogeneities. Frequency-swept hyperbolic secant and adiabatic time-optimal saturation pulse inputs were found to work best in the optimizations, and the pulse lengths required to selectivity saturate the magnetization were always found to be less than the inversion recovery delay, T1ln(2). The selectivity of the optimized relaxation selective pulses was experimentally demonstrated in aqueous solutions with varying concentrations of the paramagnetic species, [Mn(+2)], and for use in solvent suppression. Finally, the "rotational" properties of spin relaxation were explored along with an analytical derivation of adiabatic time-optimal saturation pulses.
authors.affiliation: Department of Chemistry, University of Miami, Coral Gables, FL 33124, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lopez
authors.affiliation: Department of Chemistry, University of Miami, Coral Gables, FL 33124, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.affiliation: Department of Chemistry, University of Miami, Coral Gables, FL 33124, United States. Electronic address: jwalls@miami.edu.
authors.forename: Jamie D
authors.initials: JD
authors.lastname: Walls
keywords: GRAPE algorithm; Relaxation; Saturation profile; Selective pulses