000196889 001__ 196889
000196889 005__ 20190416220314.0
000196889 0247_ $$2doi$$a10.1016/j.jmr.2013.09.003
000196889 022__ $$a1090-7807 000196889 02470$$2ISI$$a000329149200014 000196889 037__$$aARTICLE
000196889 245__ $$aBroadband excitation in solid-state NMR using interleaved DANTE pulse trains with N pulses per rotor period 000196889 269__$$a2013
000196889 260__ $$bElsevier$$c2013$$aSan Diego 000196889 300__$$a12
000196889 336__ $$aJournal Articles 000196889 520__$$aWe analyze the direct excitation of wide one-dimensional spectra of nuclei with spin I = 1/2 or 1 in rotating solids submitted to pulse trains in the manner of Delays Alternating with Nutations for Tailored Excitation (DANTE), either with one short rotor-synchronized pulse of duration tau(p) in each of K rotor periods (D-1(k)) or with N interleaved equally spaced pulses tau(p) in each rotor period, globally also extending over K rotor periods (D-N(k) ). The excitation profile of (D-N(K)),scheme is a comb of rf-spikelets with Nv(R) = N/T-R spacing from the carrier frequency, and a width of each spikelet inversely proportional to the length, KTR, of D-N(K) scheme. Since the individual pulse lengths, tau(p), are typically of a few hundreds of ns, D-N(K) scheme can readily excite spinning sidebands families covering several MHz, provided the rf carrier frequency is close enough to the resonance frequency of one the spinning sidebands. If the difference of isotropic chemical shifts between distinct chemical sites is less than about 1.35/(KTR, D-1(k) scheme can excite the spinning sidebands families of several sites. For nuclei with I = 1/2, if the homogeneous and inhomogeneous decays of coherences during the DANTE sequence are neglected, the K pulses of a Dfic train have a linearly cumulative effect, so that the total nutation angle is 0(tot) = K2 pi v(1)tau(p), where vl is the rf-field amplitude. This allows obtaining nearly ideal 90 degrees pulses for excitation or 180 degrees rotations for inversion and refocusing across wide MAS spectra comprising many spinning sidebands. If one uses interleaved DANTE trains D-N(k) with N >1, only spinning sidebands separated by intervals of Nv(R) with respect to the carrier frequency are observed as if the effective spinning speed was Nv(R). The other sidebands have vanishing intensities because of the cancellation of the N contributions with opposite signs. However, the intensities of the remaining sidebands obey the same rules as in spectra obtained with V-R. With increasing N, the intensities of the non-vanishing sidebands increase, but the total intensity integrated over all sidebands decreases. Furthermore, the NK pulses in a D-N(k) train do not have a simple cumulative effect and the optimal cumulated flip angle for optimal excitation, O-tot(opt) = NK2ru1 Tp exceeds 90. Such D/, pulse trains allow achieving efficient broadband excitation, but they are not recommended for broadband inversion or refocusing as they cannot provide proper 180 rotations. Since D-N(k), pulse trains with N> I are shorter than basic D-1(k) sequences, they are useful for broadband excitation in samples with rapid homogeneous or inhomogeneous decay. For nuclei with I =1 (e.g., for N-14), the response to basic D-1(k) pulse train is moreover affected by inhomogeneous decay due to 2nd-order quadrupole interactions, since these are not of rank 2 and therefore cannot be eliminated by spinning about the magic angle. For large quadrupole interactions, the signal decay produced by second-order quadrupole interaction can be minimized by (i) reducing the length of D-1(k) pulse trains using N> 1, (ii) fast spinning, (iii) large rf-field, and (iv) using high magnetic fields to reduce the 2nd-order quadrupole interaction. (C) 2013 Elsevier Inc. All rights reserved.
000196889 6531_ $$a1D solid-state NMR 000196889 6531_$$aN-14
000196889 6531_ $$aBroadband excitation 000196889 6531_$$aDANTE
000196889 6531_ $$aMAS 000196889 6531_$$aParamagnetic samples
000196889 700__ $$uLille North France Univ, CNRS, UMR 8181, UCCS, F-59652 Villeneuve Dascq, France$$aLu, Xingyu
000196889 700__ $$uLille North France Univ, CNRS, UMR 8181, UCCS, F-59652 Villeneuve Dascq, France$$aTrebosc, Julien
000196889 700__ $$uLille North France Univ, CNRS, UMR 8181, UCCS, F-59652 Villeneuve Dascq, France$$aLafon, Olivier
000196889 700__ $$0244126$$g205378$$uEcole Polytech Fed Lausanne, ISIC, CH-1015 Lausanne, Switzerland$$aCarnevale, Diego
000196889 700__ $$0243131$$g176695$$uEcole Polytech Fed Lausanne, ISIC, CH-1015 Lausanne, Switzerland$$aUlzega, Simone
000196889 700__ $$g122795$$uEcole Polytech Fed Lausanne, ISIC, CH-1015 Lausanne, Switzerland$$aBodenhausen, Geoffrey$$0243177
000196889 700__ $$aAmoureux, Jean-Paul$$uLille North France Univ, CNRS, UMR 8181, UCCS, F-59652 Villeneuve Dascq, France
000196889 773__ $$j236$$tJournal Of Magnetic Resonance$$q105-116 000196889 8564_$$uhttps://infoscience.epfl.ch/record/196889/files/P366-Lu-Trebosc-Lafon-Carnevale-Ulzega-Bodenhausen-Amoureux-DANTE-N2-JMR-236-105-2013%20copy.pdf$$zn/a$$s3631415$$yn/a 000196889 8564_$$uhttps://infoscience.epfl.ch/record/196889/files/P366a-Supp-Lu-Trebosc-Lafon-Carnevale-Ulzega-Bodenhausen-Amoureux-DANTE-N2-JMR-236-105-2013.pptx$$zn/a$$s1697991
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000196889 937__ $$aEPFL-ARTICLE-196889 000196889 973__$$rREVIEWED$$sPUBLISHED$$aEPFL
000196889 980__ aARTICLE`