A broadband pulse EPR spectrometer for high-throughput measurements in the X-band

A broadband pulse EPR spectrometer for high-throughput measurements in the X-band Full article

Journal

Journal of Magnetic Resonance Open
, E-ISSN: 2666-4410

Output data

Year: 2023, Volume: 14-15, Article number : 100092, Pages count : 10 DOI: 10.1016/j.jmro.2022.100092

Tags

Pulse EPR; Low noise; Fourier transform measurements; Uniform broadband excitation; Chirped adiabatic WURST pulses; Broadband ESEEM

Authors

Isaev Nikolay P. ¹ , Melnikov Anatoly R. ² , Lomanovich Konstantin A. ³ , Dugin Mikhail V. ⁴ , Ivanov Mikhail Yu. ² , Polovyanenko Dmitriy N. ³ , Veber Sergey L. ² , Bowman Michael K. ^3,5 , Bagryanskaya Elena G. ³

Affiliations

1	Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS
2	International Tomography Center SB RAS
3	N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry of Siberian Branch of Russian Academy of Sciences
4	Micran Ltd., Kirova Avenue 51d
5	University of Alabama, Tuscaloosa

Funding (1)

Российский Научный Фонд

21-14-00219

We present an X-band pulse EPR spectrometer with high throughput and excellent sensitivity in the 8.5-11.5GHz range. It is designed for high stability and low noise Fourier Transform measurements for applications in pulse dipolar spectroscopy, pulse hyperfine spectroscopy, and spin relaxation from cryogenic temperatures to room temperature. An arbitrary waveform generator is used to generate pulses of any frequency and shape for multiple resonance experiments or for uniform broadband excitation with bandwidths exceeding 350 MHz. We illustrate the capabilities and performance of the spectrometer by measurements on free radicals and biradicals in solids and liquids. Relaxation times of radicals in liquid solution are measured for fewer than 30,000,000 spins (less than 3 nanomoles per liter). Non-uniform acquisition provides higher throughput for mixtures of radicals with quite different relaxation rates. Conventional DEER measurements on a rigid biradical have good modulation depth. Broadband SIFTER with chirped adiabatic WURST pulses demonstrates versatility for the latest broadband pulse schemes. A broadband ESEEM measurement correlates ESEEM and EPR frequencies which characterize the conformation of a nitroxide radical. The entire EPR spectrum with a width approaching 300 MHz was excited and detected throughout the measurement. The spectrometer supports the operator in tuning, setting up experiments and monitoring their progress so that even novice users consistently can obtain optimal results.

Isaev N.P. , Melnikov A.R. , Lomanovich K.A. , Dugin M.V. , Ivanov M.Y. , Polovyanenko D.N. , Veber S.L. , Bowman M.K. , Bagryanskaya E.G.
A broadband pulse EPR spectrometer for high-throughput measurements in the X-band
Journal of Magnetic Resonance Open. 2023. V.14-15. 100092 :1-10. DOI: 10.1016/j.jmro.2022.100092 WOS Scopus РИНЦ

Published online:	Dec 27, 2022
Published print:	Dec 28, 2022

Web of science	WOS:001133323900001
Scopus	2-s2.0-85159339798
Elibrary	60241475
OpenAlex	W4313419880