SF_(6)分子的10.6μm高分辨射流冷却激光吸收光谱  

High-resolution jet-cooled laser absorption spectra of SF_(6) at 10.6μm

作　　者：袁洪瑞 刘涛[1,2] 朱天鑫 刘云 李响 陈杨 段传喜 Yuan Hong-Rui;Liu Tao;Zhu Tian-Xin;Liu Yun;Li Xiang;Chen Yang;Duan Chuan-Xi(Research Institute of Physical and Chemical Engineering for Nuclear Industry,Tianjin 300180,China;Science and Technology on Particle Transport and Separation Laboratory,Tianjin 300180,China;College of Physical Science and Technology,Central China Normal University,Wuhan 430079,China)

机构地区：[1]核工业理化工程研究院,天津300180 [2]粒子输运与富集技术国防科技重点实验室,天津300180 [3]华中师范大学物理科学与技术学院,武汉430079

出　　处：《物理学报》2023年第6期89-95,共7页Acta Physica Sinica

基　　金：粒子输运与富集技术国防科技重点实验室基金资助的课题.

摘　　要：六氟化硫(SF_(6))是一种长寿命的温室气体,其红外吸收光谱对模拟大气辐射平衡非常重要.SF_(6)也是研究激光分离同位素原理和技术的典型体系之一.由于SF_(6)分子较重,其室温下的红外光谱非常密集,给利用吸收光谱技术监测不同SF_(6)同位素分子的相对浓度带来很大困难.本文利用超声射流冷却和像散型多程吸收池技术,测量了32SF_(6)和33SF_(6)同位素分子在10.6μm波段的高分辨红外激光吸收光谱.处于振动基态的32SF_(6)和33SF_(6)分子在狭缝型超声射流中的转动温度约为10 K,谱线线宽约为0.0008 cm^(-1).在此条件下观测到了SF_(6)一个新的热带,其Q支的位置在941.0 cm^(-1)附近.将其初步归属为32SF_(6)的(v1+v2+v3)–(v1+v2)带,对该热带进行简化的转动分析,并讨论利用该热带和33SF_(6)的v3基频带进行33SF_(6)/32SF_(6)的相对浓度监测的可行性.Sulfur hexafluoride(SF_(6))is a greenhouse gas of very long lifetime.Its infrared absorption spectrum is very important in modeling the atmospheric radiation balances.The SF_(6) is also a prototypical system for studying the principles and techniques of laser isotope separation using powerful infrared lasers.As a very heavy molecule,the infrared spectrum of SF_(6) at room temperature is very dense,which poses a great challenge to monitoring the relative abundances of different SF_(6) isotopomers by direct absorption spectroscopy.Supersonic jet expansions have been widely used to simplify the gas phase molecular spectra.In this work,astigmatic multi-pass absorption cell and distributed feed-back quantum cascade lasers(QCLs)are used to measure jet-cooled rovibrational absorption spectra of 32SF_(6) and 33SF_(6) at 10.6μm.The spectrometer works in a segmented rapid-scan mode.The gas mixtures(SF_(6)∶Ar∶He=0.12∶1∶100)are expanded through an 80 mm 300μm pulsed slit nozzle.Two QCLs running at room temperature are used and each one covers a spectral range of about 3.0 cm^(-1).The v3 fundamental bands of both 32SF_(6) and 33SF_(6) are observed.The rotational temperature of 32SF_(6) and 33SF_(6) in the ground state in the supersonic jet are both estimated at 10 K and the linewidth is about 0.0008 cm^(-1) by comparing the simulated spectrum with the observed spectrum with the PGOPHER program.A new weak vibrational band centered around 941.0 cm^(-1) is observed and tentatively assigned to the(v_(1)+v_(2)+v_(3))-(v_(1)+v_(2))hot band of 32SF_(6).The effective Hamiltonian used to analyze the rovibrational spectrum of SF_(6) is briefly introduced.A simplified rotational analysis for this hot band is performed with the XTDS program developed by the Dijon group.The band-origin of this hot band is determined to be 941.1785(21)cm^(-1).The rotational temperature of this hot band is estimated at 50 K.A new scheme by measuring the jet-cooled absorption spectrum of this hot band of 32SF6 and the v3 fundamental band of 33SF_(6

关 键 词：振动转动光谱 温室气体 同位素分离 超声射流 

分 类 号：X831[环境科学与工程—环境工程] O657.3[理学—分析化学]