Recently, the team of Zhang Weijun, a researcher at Ankuang Institute, Hefei Institute of Materials, Chinese Academy of Sciences (CAS), has made a new progress in time-resolved frequency-modulated magnetic rotation spectroscopy detection technology, and the related research results have been published in the Optics Express, published by Optical Society of America (OSA), under the title of "High-bandwidth Mid-Infrared Frequency Modulated Magnetic Rotational Spectrometry for Time-Resolved Measurement of OH Radicals".
OH radicals are the most important oxidizing agents in the atmosphere, initiating most of the oxidation reactions in the tropospheric atmosphere, and their low concentrations and short lifetimes make their sensitive and rapid detection extremely important for in-depth studies of their chemical reaction kinetics and mechanisms, as well as for clarifying the causes of atmospheric pollution.
The frequency-modulated magnetic rotation spectroscopy (FMRS) technique developed by the team, including researcher Zhao Weixiong and Dr. Cheng Feihu, for the highly sensitive and rapid measurement of OH radicals is characterized by high time resolution, high sensitivity, and good selectivity, which is particularly suitable for kinetic studies of short-lived radicals and intermediates. In the experiment, for the OH radical generated by 266 nm pulsed laser, the researchers used the technique to measure the time-resolved spectral signals near 2.8 μm, and after three pulse averaging, the detection line of OH reaches 6.8 × 10 8 molecules/cubic centimeter (1 σ, 0.2 ms), and the detection line can be further reduced to 8.0 × 10 7 molecules/cubic centimeter after 100 averaging. This technique is applicable not only to OH radicals but also to other paramagnetic transient molecules, and will provide a new and important measurement tool for the study of radical dynamics.
This research was supported by the National Natural Science Foundation of China, the Young Innovators Promotion Association of the Chinese Academy of Sciences, and the Director's Fund of Hefei Institute of Materials Science, Chinese Academy of Sciences.
Science Island team makes new progress in time-resolved frequency-modulated magnetic rotation spectroscopy detection technology
Schematic diagram of the frequency-modulated magnetic rotation spectroscopy device
The Science Island team has made new progress in time-resolved frequency-modulated magnetic rotation spectroscopy detection technology.
Time-decay curve of OH radical concentration
The Science Island team has made new progress in time-resolved frequency-modulated magnetic rotation spectroscopy detection technology.
(a) Monitoring of OH radical concentration; (b) Allen deviation of OH radical concentration
