TY - JOUR

T1 - Recoupling of Heteronuclear Dipolar Interactions with Rotational-Echo Double-Resonance at High Magic-Angle Spinning Frequencies

AU - Jaroniec, Christopher P.

AU - Tounge, Brett A.

AU - Rienstra, Chad M.

AU - Herzfeld, Judith

AU - Griffin, Robert G.

N1 - Funding Information:
We thank M. Hohwy for the FORTRAN subroutines used in the numerical simulations and acknowledge many helpful discussions with B. Reif and M. Hohwy. C.P.J. thanks the NSF for a Predoctoral Fellowship, B.A.T. thanks the American Cancer Society for a Postdoctoral Fellowship (PF-99-260-01-GMC), and C.M.R. thanks the Howard Hughes Medical Institute for a Predoctoral Fellowship. This research was also supported by NIH grants GM-23289, GM-36810, and RR-00995.

PY - 2000/9

Y1 - 2000/9

N2 - Heteronuclear dipolar recoupling with rotational-echo double-resonance (REDOR) is investigated in the rapid magic-angle spinning regime, where radiofrequency irradiation occupies a significant fraction of the rotor period (10-60%). We demonstrate, in two model 13C-15N spin systems, [1-13C, 15N] and [2-13C, 15N]glycine, that REDOR ΔS/S0 curves acquired at high MAS rates and relatively low recoupling fields are nearly identical to the ΔS/S0 curve expected for REDOR with ideal δ-function pulses. The only noticeable effect of the finite π pulse length on the recoupling is a minor scaling of the dipolar oscillation frequency. Experimental results are explained using both numerical calculations and average Hamiltonian theory, which is used to derive analytical expressions for evolution under REDOR recoupling sequences with different π pulse phasing schemes. For xy-4 and extensions thereof, finite pulses scale only the dipolar oscillation frequency by a well-defined factor. For other phasing schemes (e.g., xx-4 and xx̄-4) both the frequency and amplitude of the oscillation are expected to change.

AB - Heteronuclear dipolar recoupling with rotational-echo double-resonance (REDOR) is investigated in the rapid magic-angle spinning regime, where radiofrequency irradiation occupies a significant fraction of the rotor period (10-60%). We demonstrate, in two model 13C-15N spin systems, [1-13C, 15N] and [2-13C, 15N]glycine, that REDOR ΔS/S0 curves acquired at high MAS rates and relatively low recoupling fields are nearly identical to the ΔS/S0 curve expected for REDOR with ideal δ-function pulses. The only noticeable effect of the finite π pulse length on the recoupling is a minor scaling of the dipolar oscillation frequency. Experimental results are explained using both numerical calculations and average Hamiltonian theory, which is used to derive analytical expressions for evolution under REDOR recoupling sequences with different π pulse phasing schemes. For xy-4 and extensions thereof, finite pulses scale only the dipolar oscillation frequency by a well-defined factor. For other phasing schemes (e.g., xx-4 and xx̄-4) both the frequency and amplitude of the oscillation are expected to change.

KW - Finite pulse effects

KW - Hetero-nuclear dipolar recoupling

KW - Magic-angle spinning

KW - Rotational-echo double-resonance

KW - Solid-state NMR

UR - http://www.scopus.com/inward/record.url?scp=0034264324&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034264324&partnerID=8YFLogxK

U2 - 10.1006/jmre.2000.2128

DO - 10.1006/jmre.2000.2128

M3 - Article

C2 - 10968966

AN - SCOPUS:0034264324

VL - 146

SP - 132

EP - 139

JO - Journal of Magnetic Resonance

JF - Journal of Magnetic Resonance

SN - 1090-7807

IS - 1

ER -