共聚焦拉曼测量中激光焦点在球形液滴中的穿透深度.pdf

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1、物理化学学报(WuliHuaxueXuebao)AprilActa尸．一Chim．Sin．2011，27(4)，769—773769[Article】WWW．whxb．pku．edu．ca-I+／、聚焦拉曼测量中激光焦点在球形液滴中的穿透深度王枫z章岳张韫宏f河南理工大学物理化学学院化学系，河南焦作454000；北京理工大学理学院化学物理研究所，北京100081)摘要：针对在共聚焦拉曼测量中激光在球形液滴中的聚焦问题建立理论模型，推导出激光焦点在球形液滴中的穿透深度公式，将激光焦点在球形液滴中的实际穿透深度和拉曼平台的垂直移动距离关联起来．研究表明，平台移动距离和激光焦点移动距离是非

2、线性的，激光焦点分别聚焦于液滴上表面和球心处时，激光焦点的移动距离等于平台移动距离，而当激光焦点在液滴上表面和液滴球心之间时，激光焦点的移动距离大于平台移动距离．并利用此结论初步获得MgSO球形液滴胶态结构的空间分布信息．发现MgSO液滴在低湿度下形成的胶态结构是具有一定厚度的壳状结构，且其厚度与液滴所处环境的相对湿度有关．关键词：共聚焦拉曼：穿透深度：球形液滴：激光焦点；胶态结构：硫酸镁中图分类号：0645；0648PenetratingDepthofLaserFocusinaSphericalDropletduringConfocaIRamanMeasurementsWANGFe

3、ng’I·ZHANGYueZHANGYun—HongDepartmentofChemistry,SchoolofPhysicsandChem&try,HenanPolytechnicUniversity,Jiaozuo454000,HenanProvincePRChina；2InstituteofChemicalPhysics,SchoolofScience,Beij'ingInstituteofTechnology,Beij'ing100081．P’R．China)Abstract：lnthispaperweattempttoestablishatheoreticaImodeIto

4、dea1withtheIaserfocusingproblemduringconfocaIRamanmeasurementswithinasphericaldroplet。AdepthpenetrationformulawasdeducedandtheactuaIpenetratingdepthoftheIaserfoCUSinasphericaldropletwasrelatedtotheverticalmovingdistanceofaRamanspectrographSplatform．Theresultsindicatethatanonlinearcorrelationexi

5、stsbetweentheplatformSmovingdistanceandthemovingdistanceoftheIaserfoCUS．ThemovingdistanceofthelaserspotiSequaItothemovingdistanceoftheplatformwhenthelaserfoCUSiSlocatedattheSUrfaceoratthecenterofthedroplet．However．themovingdistanceofthelaserspotiSfoundtobelongerthanthemovingdistanceoftheplatfor

6、mwhenthelaseriSfocusedatthezonebetweenthesurfaceandthecenter．Therefore，spatialdistributioninformationfortheMgS04dropletgelstructurecanbeobtainedaccordingtotheabove．mentionedconclusion．WefoundthatthegelationofanMgS04dropletunderlOWrelativehumidity(RH)wasashellstructurewithacertainthicknessandthi

7、sthicknesswascloselyrelatedtotherelativehumidityofthelocaIenvironment．KeyWords：ConfocalRaman；Penetratingdepth；Sphericaldroplet；Laserfocus；GelstrucutreMagnesiumsulfateReceived：December31，2010；Revised：January30，2011；PublishedonWeb：F