Study on the Near-Infrared Spectra of Sarin Based on Density
Functional Theory
SUN Zhi-shen1, LIU Yong-gang2, 3, ZHANG Xu1, GUO Teng-xiao1*, CAO Shu-ya1*
1. State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
2. State Key Laboratory of Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China
3. Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010, China
Abstract：Near-infrared spectroscopy is mainly the overtones and combination bands absorption spectra of organic molecules, which are generated by the overtones and combination bands of hydrogen-containing groups such as C—H, N—H, O—H, etc., which can obtain molecular structure, composition, state and other information. This technology is an important method for studying the vibration information of hydrogen-containing groups in organic matter and is often used for qualitative and quantitative analysis of biological substances such as food and crops. The research objects in the biochemical field also have hydrogen-containing groups. These hydrogen-containing groups have strong absorption frequency characteristics, are less affected by the internal and external environment of the molecule, and have more stable spectral characteristics in the near-infrared spectrum. This technology can be used to detect chemical warfare agents and hazardous chemicals. Sarin is a neurotoxic chemical agent. When studying its structure, chemical properties and spectral properties, in order to ensure safety, simulants are often used in the experiment to substitute for testing, but there is no fair near-infrared simulant for sarin. This paper uses density functional theory (DFT), based on the Gaussian program package, and uses B3LYP/def2-SVP to optimize the ground state structure of the sarin molecule, and calculates the fine structure of the sarin molecule and the fundamental frequency vibration mode of the molecule. The generalized second-order perturbation theory (GVPT2) is introduced to establish a theoretical model for simulating the near-infrared spectrum of biochemical poisons, obtaining the near-infrared vibration peaks and main vibration modes, and the near-infrared spectrum drawn from the vibrations of overtones and combination bands. Analyze the hydrogen-containing groups of sarin in the near-infrared region, use this method to identify its characteristic peaks, obtain three characteristic peaks of sarin molecules at 1 150, 1 362 and 1 500 nm and analyze their vibration modes. Among them, the position at 1 150 nm is produced by the contribution of multiple overtones and combination bands vibration. 1 362 nm is a wide absorption vibration region, mainly caused by the combination bands of atoms connected to C atoms in the molecule and other non-C, H atoms. The near-infrared vibration peak at 1 500 nm is mainly caused by the C8 Related vibration mode contribution. In this paper, the theoretical model of Sarin’s near-infrared spectroscopy is established through density functional theory, and the feasibility of the theoretical model is verified through experiments, which provides theoretical support for finding its near-infrared spectroscopy simulation agent.
Key words：Chemical warfare agents (CWA); Near infrared spectrum; Time-dependent density functional theory (TDDFT)
孙梽珅，刘永刚，张 旭，郭腾霄，曹树亚. 基于密度泛函理论的沙林毒剂近红外光谱研究[J]. 光谱学与光谱分析, 2023, 43(06): 1765-1769.
SUN Zhi-shen, LIU Yong-gang, ZHANG Xu, GUO Teng-xiao, CAO Shu-ya. Study on the Near-Infrared Spectra of Sarin Based on Density
Functional Theory. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2023, 43(06): 1765-1769.
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