This paper discusses the implementation and optimization bined to improve the performance of selective pulses in solidof selective-inversion pulses for deuteron powder patterns. state deuteron NMR. Efficient off-resonance selective inversion of While the theory appears analogous to liquid-state selective deuterons requires simultaneous irradiation of both spin-1 transiinversion, the implementation for solid-state deuteron NMR tions, i.e., at symmetric offsets from the Larmor frequency ( n 0 { can be dramatically different. Three essential features will D). This is best accomplished with double-sideband-modulated be discussed in detail: the need for simultaneous inversion pulses. Frequency-selective profiles can be improved by shaping of both quadrupolar transitions, shaping the pulse to improve the RF pulses. A variety of commonly used selective pulse shapes selectivity, and effects of relaxation (T 2 and T 1Z ).
are evaluated for their applicability to solid-state deuteron powder
To achieve efficient off-resonance selective inversion it patterns. A new pulse shape is introduced; the squared isosceles triangle. Generally, pulses with low bandwidth-duration product, is necessary to selectively excite both transitions of the spinsuch as the Gaussian envelope, are found to be the most effective 1 nucleus ( 14). Schemes for accomplishing this include for selective inversion in solid-state 2 H NMR. This is a consequence DANTE (10,12) and double sideband modulation (DSBM) of the large inhomogeneous quadrupolar interaction and fast, an-(14-16). It will be shown that due to the width of inhomoisotropic spin-spin relaxation. แญง 1996 Academic Press, Inc.
geneous powder patterns and spectrometer constraints, DSBM is more flexible and better suited to solid-state deuteron applications.