biostudies-literatureMillen MSwiss National Science Foundation7228-7235https://www.ebi.ac.uk/biostudies/studies/S-EPMC11261599biostudies-literatureUnknown15(28)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. FurthermoThe journal of physical chemistry lettersFrequency-Chirped Magic Angle Spinning Dynamic Nuclear Polarization Combined with Electron Decoupling.PMC11261599219514201070Saliba EPBjorgvinsdottir SPagonakis IGAlaniva NMillen MSigurdsson STOverall SADapp ABarnes ABfalseFrequency-Chirped Magic Angle Spinning Dynamic Nuclear Polarization Combined with Electron Decoupling.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. Furthermo2024-01-01T00:00:00Z2024 Jul2025-04-04T14:46:44.011Z2025-04-04T14:46:44.011ZS-EPMC112615993897590510.1021/acs.jpclett.4c01075