TY - JOUR
T1 - Frequency-Chirped Magic Angle Spinning Dynamic Nuclear Polarization Combined with Electron Decoupling
AU - Millen, Marthe
AU - Alaniva, Nicholas
AU - Saliba, Edward P.
AU - Overall, Sarah A.
AU - Däpp, Alexander
AU - Pagonakis, Ioannis Gr
AU - Sigurdsson, Snorri Th
AU - Björgvinsdóttir, Snædís
AU - Barnes, Alexander B.
N1 - Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society.
PY - 2024/7/18
Y1 - 2024/7/18
N2 - Magic angle spinning (MAS) dynamic nuclear polarization (DNP) increases the signal intensity of solid-state nuclear magnetic resonance. DNP typically uses continuous wave (CW) microwave irradiation close to the resonance frequency of unpaired electron spins. In this study, we demonstrate that frequency-chirped microwaves improve DNP performance under MAS. By modulating the gyrotron anode potential, we generate a train of microwave chirps with a maximum bandwidth of 310 MHz and a maximum incident power on the spinning sample of 18 W. We characterize the efficiency of chirped DNP using the following polarizing agents: TEMTriPol-1, AsymPolPOK, AMUPol, and Finland trityl. The effects of different chirp widths and periods are analyzed at different MAS frequencies and microwave powers. Furthermore, we show that chirped DNP can be combined with electron decoupling to improve signal intensity by 59%, compared to CW DNP without electron decoupling, using Finland trityl as a polarizing agent.
AB - Magic angle spinning (MAS) dynamic nuclear polarization (DNP) increases the signal intensity of solid-state nuclear magnetic resonance. DNP typically uses continuous wave (CW) microwave irradiation close to the resonance frequency of unpaired electron spins. In this study, we demonstrate that frequency-chirped microwaves improve DNP performance under MAS. By modulating the gyrotron anode potential, we generate a train of microwave chirps with a maximum bandwidth of 310 MHz and a maximum incident power on the spinning sample of 18 W. We characterize the efficiency of chirped DNP using the following polarizing agents: TEMTriPol-1, AsymPolPOK, AMUPol, and Finland trityl. The effects of different chirp widths and periods are analyzed at different MAS frequencies and microwave powers. Furthermore, we show that chirped DNP can be combined with electron decoupling to improve signal intensity by 59%, compared to CW DNP without electron decoupling, using Finland trityl as a polarizing agent.
UR - http://www.scopus.com/inward/record.url?scp=85198091295&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.4c01075
DO - 10.1021/acs.jpclett.4c01075
M3 - Article
C2 - 38975905
AN - SCOPUS:85198091295
SN - 1948-7185
VL - 15
SP - 7228
EP - 7235
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 28
ER -