摘要
解析大气中HONO和N_(2)O_(4)的光化学循环及其来源,需要对其质量分数进行准确测量,而质量分数测量的前提是吸收线参数的准确度量。采用7.8μm室温连续量子级联激光器和长光程多次反射吸收池对实验产生的HONO和N2O4气体进行了同时测量,确定了两种气体的吸收线频率。根据已知的1280.4 cm-1处trans-HONO的吸收线强,计算得到trans-HONO的质量分数为(0.72±0.04)×10^(-6),相应的系统最低检测限为(11.15±0.50)×10^(-9)。利用中红外量子级联光谱技术同时对HONO和N_(2)O_(4)进行分析研究,所得到的谱线参数也为HONO和N2O4质量分数的实时监测、化学反应过程的分析等提供了重要的依据。
Objective The OH radicals produced by HONO photolysis are important oxidants in atmospheric reactions.The sources and mixing ratios of OH radicals are closely related to the level of HONO.The sources of HONO are still unclear under different contaminated conditions,different meteorological conditions,and different reaction conditions.HONO also has a great impact on people's health.To better understand the photochemical cycle of atmospheric HONO and its sources,the levels of HONO need to be accurately measured.N_(2)O_(4) plays an important role in liquid propellants and is also a toxic gas.It is necessary to accurately detect its levels to better understand its reaction mechanism and perform realtime monitoring.Accurate measurement of HONO and N_(2)O_(4) levels requires precise absorption line parameters,such as line positions,line intensities,and spectral line broadening.Methods In this experiment,highresolution quantum cascade laser absorption spectroscopy technology is used to measure HONO and N_(2)O_(4) gas samples.A room temperature continuous wave quantum cascade laser(CWQCL)combined with a 50 m pathlength absorption cell are used to measure the absorption line frequencies of the two gases.Using the heterogeneous reactions of NO_(2) and H_(2)O to prepare gas samples of HONO.The overall absorption line frequencies are calibrated by the two H_(2)O absorption lines at the frequencies of 1280.0475 cm-1 and 1281.1611 cm-1.According to the known HONO line intensity at 1280.4 cm-1,the level of HONO in the gas sample as well as the signaltonoise ratio and minimum detection limit of the system are calculated by the BeerLambert law and Voigt line shape fitting.Results and Discussions The absorption spectra of gas samples in the range of 1279.5-1282.5 cm-1 are obtained as shown in Fig.4.The gases that may exist in the absorption cell mainly include three types,i.e.,exhaled gases,the gases in the air,and the gases generated by the chemical reaction.The HITRAN database and published papers are used to find the possible g
作者
李亚繁
江超超
崔潇汉
俞本立
崔小娟
Li Yafan;Jiang Chaochao;Cui Xiaohan;Yu Benli;Cui Xiaojuan(Information Materials and Intelligent Sensing Laboratory of Anhui Province,Institutes of Physical Science and Information Technology,Anhui University,Hefei 230601,Anhui,China;Key Laboratory of OptoElectronic Information Acquisition and Manipulation of Ministry of Education,Anhui University,Hefei 230601,Anhui,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2023年第11期274-282,共9页
Acta Optica Sinica
基金
安徽省自然科学基金优秀青年基金(2108085Y14)
安徽省重点研究与开发计划(2022l07020026)
国家自然科学基金(41775128)。
