CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopies

Synthetic commercial type-IIa diamond crystal containing low concentration of P1 (Ns0) centers ([Ns0] <1ppm) was examined as a possible calibration standard for evaluating microwave magnetic field intensity (B1) in the spectrometer cavity. The reliability of this standard was experimentally and t...

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Main Authors: B. Rakvin, D. Carić, M. Kveder
Format: Article
Language:English
Published: Elsevier 2022-06-01
Series:Journal of Magnetic Resonance Open
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2666441022000097
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author B. Rakvin
D. Carić
M. Kveder
author_facet B. Rakvin
D. Carić
M. Kveder
author_sort B. Rakvin
collection DOAJ
description Synthetic commercial type-IIa diamond crystal containing low concentration of P1 (Ns0) centers ([Ns0] <1ppm) was examined as a possible calibration standard for evaluating microwave magnetic field intensity (B1) in the spectrometer cavity. The reliability of this standard was experimentally and theoretically tested by employing two different types of microwave cavities with different distributions of B1 values. The procedure relies on the ordinary continuous wave electron paramagnetic resonance (CW-EPR) with magnetic field modulation (ωrf/2π=100 kHz) applied under the regime of the microwave power (PMW) saturation of the out-of-phase first harmonic signal. The power saturation procedure for PMW∼B11/2 was analyzed with respect to the change of spectral lineshape when Rabi frequency (ω1=γB1, γis the electron gyromagnetic ratio) approaches to ωrf. The phenomenon of the inversion of sideband lines while passing the Rabi resonance condition (ω1=ωrf) was analyzed. In specific, from the simulation of the experimental lineshapes in the close vicinity of Rabi resonance (ω1≈ωrf) the correspondingB1 can be assigned. For the chosen diamond crystal low value of B1≈3.6µT at Rabi resonance was determined what makes it a convenient standard for DNP enhanced NMR spectroscopy which requires relatively small B1.
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spelling doaj.art-1880698f09504c0095cb3acadab8bf4c2022-12-22T00:32:16ZengElsevierJournal of Magnetic Resonance Open2666-44102022-06-0110100039CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopiesB. Rakvin0D. Carić1M. Kveder2Corresponding author.; Ruđer Bošković Institute, Division of Physical Chemistry, Bijenička 54, Zagreb, Croatia.Ruđer Bošković Institute, Division of Physical Chemistry, Bijenička 54, Zagreb, Croatia.Ruđer Bošković Institute, Division of Physical Chemistry, Bijenička 54, Zagreb, Croatia.Synthetic commercial type-IIa diamond crystal containing low concentration of P1 (Ns0) centers ([Ns0] <1ppm) was examined as a possible calibration standard for evaluating microwave magnetic field intensity (B1) in the spectrometer cavity. The reliability of this standard was experimentally and theoretically tested by employing two different types of microwave cavities with different distributions of B1 values. The procedure relies on the ordinary continuous wave electron paramagnetic resonance (CW-EPR) with magnetic field modulation (ωrf/2π=100 kHz) applied under the regime of the microwave power (PMW) saturation of the out-of-phase first harmonic signal. The power saturation procedure for PMW∼B11/2 was analyzed with respect to the change of spectral lineshape when Rabi frequency (ω1=γB1, γis the electron gyromagnetic ratio) approaches to ωrf. The phenomenon of the inversion of sideband lines while passing the Rabi resonance condition (ω1=ωrf) was analyzed. In specific, from the simulation of the experimental lineshapes in the close vicinity of Rabi resonance (ω1≈ωrf) the correspondingB1 can be assigned. For the chosen diamond crystal low value of B1≈3.6µT at Rabi resonance was determined what makes it a convenient standard for DNP enhanced NMR spectroscopy which requires relatively small B1.http://www.sciencedirect.com/science/article/pii/S2666441022000097P1 centers in diamondEPRDNPElectron spin relaxationModulation sidebands
spellingShingle B. Rakvin
D. Carić
M. Kveder
CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopies
Journal of Magnetic Resonance Open
P1 centers in diamond
EPR
DNP
Electron spin relaxation
Modulation sidebands
title CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopies
title_full CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopies
title_fullStr CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopies
title_full_unstemmed CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopies
title_short CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for B1 evaluation in EPR and DNP enhanced NMR spectroscopies
title_sort cw epr spectra of p1 centers in hpht diamond in the vicinity of rabi resonance possible standard for b1 evaluation in epr and dnp enhanced nmr spectroscopies
topic P1 centers in diamond
EPR
DNP
Electron spin relaxation
Modulation sidebands
url http://www.sciencedirect.com/science/article/pii/S2666441022000097
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