CO_2与高振动激发K_2碰撞中的全分辨转动态分布  

Full State-Resolved Rotational Distribution of CO_2 in Collisions with Highly Vibrationally Excited K_2

作　　者：王淑英[1] 戴康[1] 沈异凡[1] 

机构地区：[1]新疆大学物理科学与技术学院,新疆乌鲁木齐830046

出　　处：《光谱学与光谱分析》2017年第12期3658-3663,共6页Spectroscopy and Spectral Analysis

基　　金：国家然科学基金项目(11364042);新疆大学自然科学基金项目(BS150125)资助

摘　　要：在K_2+CO_2中,受激发射泵浦得到K_2(E=3 500和4 000cm^(-1))高位振动态,研究了高振动激发K_2与CO_2碰撞产生的CO_2全分辨转动态分布。利用高分辨瞬时激光诱导荧光(LIF)测量了CO_2(0000)J=2~74的转动和平移能量轮廓,利用双高斯函数拟合,分别确定各转动态的产生和倒空线宽,从而得到碰撞产生的Doppler展宽、平移温度和平移能。对于K_2不同的激发能E,能量转移的机制是相似的,为振动-转动/平移弛豫机制。但碰撞出现部分的平移温度均超出池温,而碰撞倒空部分的平移温度均略低于池温,平移能随E的增加而增大,E增加14%,平移能增加40%。CO_2(0000)转动态分布的半对数描绘给出了双指数分布,对于K_2E=3 500cm^(-1),低J态分布T_a=(523±60)K,高J态分布T_b=(1 890±210)K。Ta接近池温,说明低J态为近弹性碰撞,属单量子弛豫过程,而高J态为非弹性碰撞,属多量子驰豫过程。对于K_2E=4 000cm^(-1)同样有双指数行为,低J分布T_a=(620±65)K,高J分布T_b=(2 240±250)K。高振动态K_2(E)与CO_2碰撞,E=4 000cm^(-1)比E=3 500cm^(-1)的Ta和Tb均约高19%,说明转动分布对于K_2不同能量是敏感的,但弹性和非弹性分支比是基本相同的,弱碰撞约占82%,强碰撞约占18%。Highly vibrationally excited K2 （E=3500 and 4000 cm -1 ） was achieved by stimulated emission pumping .The full state-resolved distribution of scattered CO2 （0000） molecules from collisions with excited K2 （E） was reported .The donor energy dependence for full J-state distribution of energy upstate in collisions has been investigated .Nascent rotational and translational energy profiles for scattered CO2 （0000） molecules with J=2~74 were measured using high resolution transient laser induced fluorescence （LIF） .The appearance line widths were obtained by fitting the double Gaussian function to the transient line profile data at t=1 μs .Doppler-broadened line widths and the relative （center of mass frame） translational temperatures for appearance and depletion of scattered CO2 molecules ,the lab-frame translational temperatures and average translation energy of appearance section for K2 （E）/CO2 collisions were determined .The energy transfer mechanism was similar at both donor energies ,which was vibration-rotation/translation relaxation mechanism .But collisonal appearance temperatures were beyond the pool tempera-ture ,while collisonal depletion temperatures were slightly lower than the pool temperature ,and the magnitude of energy trans-ferred into translational energy increased with donor energy .The donor vibrational energy going into translational energy of the collision products was strongly dependent on the initial energy .The translational energy of the J-specific collision products in-creased by 40% or more for a 14% increase in donor vibrational energy .The nascent rotational distribution of scattered CO2 （0000） molecules was shown for collisions with K2 （E=3500 cm -1 ） .The semilog plot showed evidence of a biexponential distri-bution .A better description of the nascent rotational distribution came from fitting with the sum of two independent distribu-tions .The fitting yielded a low-energy distribution with Ta = （523 ± 60） K and a high energy distribution with

关 键 词：碰撞能量转移 受激发射泵浦 瞬时荧光测量 出现和倒空轮廓 高振动激发K2 CO2 

分 类 号：O561.5[理学—原子与分子物理]