摘要
利用高分辨率瞬时激光光谱技术，研究了 H2（1，1）与CO2碰撞中的能量转移。受激拉曼泵浦把 H2（0，1）激发到 H2（1，1）能级，H2（1，1）与 CO2碰撞，使 CO2的振转态得到布居，通过泛频吸收得到 CO2（00^0 0）和（00^0 1）的转动态分布，测量 H2（0，1）和 H2（1，1）的CARS（相干反斯托克斯拉曼散射）谱，得到这二个能级布居数密度之比，而 H2（0，1）密度通过在池温300 K下 H2（v＝0）的转动Boltzmann分布得到。碰撞转移速率系数由一个速率方程得到，对于CO2（00^0 0）J＝48～76，速率系数ktr从（3．9±0．8）×10^-11单调递增到（1．4±0．3）×10^-10 cm^3·molecule^-1·s^-1，而对于（00^0 1）J＝5～33，速率系数均在（4．3±0．9）×10^-12 cm^3·molecule^-1·s^-1附近。随 H2（1，1）的激发，在0．5μs 内测量CO2（00^0 0）和（00^0 1）原生态的转动布居，得到玻尔兹曼转动温度Trot，对于（00^0 0）态，有Trot＝1100 K，对于（00^0 1）态有Trot＝310 K，与池温接近。利用泛频吸收线的多普勒增宽测量，得到CO2各转动态的实验室平移温度Ttran和质心平移温度Trel ，对于（00^0 0）J＝48和76，Trel分别为454和1532 K，平动能平均变化在231～1848 cm^-1之间，而对于（00^0 1）J＝5～33，平均平动能基本无变化。
Energy transfer in H2 （1 ,1 ）＋CO2 collisions was investigated using high resolution transient laser spectroscopy.Rota-tional state selective excitation ofν= 1 for rotational level J= 1 was achieved by stimulated Raman pumping.Energy gain into CO2 resulting from collisions with H2 （1,1）was probed using transient absorption techniques,Distributions of nascent CO2 rota-tional populations in both the ground （00^0 0）state and the vibrationally excited （00^0 1）state were determined from overtone ab-sorption measurements.Translational energy distributions of the recoiling CO2 in individual rovibrational states were determined through measurement of Doppler-broadened transient line shapes.A kinetic model was developed to describe rates for appearance of CO2 states resulting from collisions with H2 （1 ,1 ）.From scanned CARS（coherent anti-stokes raman scattering）the spectral peaks population ratio n0/n1 was obtained,where n0 and n1 represent the number densities of H2 at the levels （0,1）and （1,1）, respectively.Using rotational Boltzmann distribution of H2 （ν= 0）at 300 K,n1 was yielded.Values for rate coefficients were ob-tained using data for CO2（00^0 0）J= 48 to 76 and CO2（00^0 1）J= 5 to 33.The rate coefficients derived from appearance of the （00^0 0）state have values of ktr= （3. 9±0. 8）×10^-11 cm3 ·molecule^-1 ·s^-1 for J= 48 and ktr= （1. 4±0. 3）×10^-10 cm^3 ·mole-cule^-1 ·s-^1 for J= 76,with a monotonic increase for the higher J states.For the （00^0 1）state,values of ktr remain fairly con-stant at ktr= （4. 3±0. 9）×10^-12 cm^3 ·molecule^-1 ·s^-1 .Rotational populations for the nascent CO2 states were measured at 0. 5μs following excitation of H2 .The transient population for each state was fit using a Boltzmann rotational distribution.The CO2 （00^0 0）J= 48~76 rotational states were populated substantially relative to the initial 300 K CO2 distributions,and the distribu-tion is described by Trot.The excited （00^0 1 ）state has Trot= 310
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2014年第6期1492-1496,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(11164028)资助
