激光诱导铝纳米膜熔化机理的分子动力学模拟.pdf

《激光诱导铝纳米膜熔化机理的分子动力学模拟.pdf》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、物理化学学~E(WuliHuaxueXuebao)DecemberActaPhys．-Chim．Sin．．2010，26(12)：3143-31493143[Article]www．whxb．pku．edu．cn激光诱导铝纳米膜熔化机理的分子动力学模拟白明泽程丽’唐红’豆育升，(重庆邮电大学计算化学研究所，重庆400065；DepartmentofPhysicalSciences，NichollsStateUniversity,LA70310，USA)摘要：采用耦合一维双温模型的分子动力学方法研究了纳米级的铝膜在飞秒激光辐照下的熔化机制．这种方法不仅能够在原子水平上展现金属膜的各种微观行为，还

2、能有效地描述金属膜的激光能量吸收、传递和金属电子热传导等过程．模拟结果表明，与其它金属相比，铝膜在飞秒激光辐照下的电子温度、晶格温度以及内部压力等呈现出不同的变化．铝膜在较高强度激光辐照下会很快发生全局一致的熔化，这与镍膜上下非均匀的熔化不同．并且由于铝的电子一声子耦合强度较高导致铝膜较镍膜和金膜熔化得更快．模拟结果显示，铝膜的熔化时间与实验测量的超快激光诱导的铝膜熔化时间一致．进而从理论上支持激光诱导的铝膜熔化是一个热力学熔化过程．关键词：金属铝：激光熔化：双温模型：超快动力学：热力学熔化中图分类号：0641：0643MolecularDynamicsSimulationoftheLaser

3、-InducedMeltingofanAINanofilmBAIMing—Ze’CHENGLi’TANGHong’DOUYu-Sheng’_l(InstitueofComputationalChemistry,ChongqingUniversityofPos~andTelecommunications，Chongqing400065,R．China；ZDepartmentofPhysicalSciences,Nichol~StateUniversity,LA70310,USAAbstract：AcoupledcomputationaItechnique．whichcombinestheoned

4、imensionaltwo．temperaturemodeIandmoleculardynamics．wasusedtostudythemeltingdynamicsofananoscalealuminumf¨mirradiatedbyafemtosecondIaserpulse．ThemodeliScapableofprovidinganatomic-leveIdepictionoffastmicroscaleprocessesinmetalsandgivesanadequatedescriptionoflaserlightabsorption，energytransfer,andfaste

5、lectronheatconductioninmetals．Thesimulationrevealedthattheelectrontemperature．1atticetemperature．andIaserinducedpressureoftheAlf¨mweresignificantlydifferentfr0mthoseofNiandAuf¨ms．TheAlf¨mmeltsgloballysoonafterIaserradiationandthisiSdifierentfromtheNif¨m．whichgoesthroughastepmeltingprocess．1naddition

6、．theAImshowsamuchfastermeltingprocessthantheNiandAufilmsbecauseofstrongelectron—phononcoupling．ThemeltingtimeoftheAIf¨mbyanultrafastlaserpulseiSconsistentwithrecentexperimentaIobservations．whichsupportstheassertionthatthelaserinducedmeltingofanAIfiImiSathermaIprocess．KeyWords：MetalAI；Lasermelting；Tw

7、o-temperaturemodel；UltrafastdynamicsThermalmeltingReceived：July22，2010；Revised：October12，2010；PublishedonWleb：November10．2010．‘Correspondingauthor．Email：Yusheng．Dou@niehollsedu；Tel：+86—23—62461438．The