高振动激发态KH(X~1∑~+,V=14～21)与CO_2碰撞中的振动-转动能量转移
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摘要
利用泵浦-探测技术研究高振动激发态KH(V=14~21)分子与CO_2的振动-转动碰撞转移过程。脉冲激光激发KH分子至高位振动态,与CO_2发生振动-转动能量转移,使CO_2高位转动态得到布居,通过测量CO_2(00~00,J=32~48)转动态分布,得到其平均转动能和平均转动能变化,发现振动量子数V从14增加至21时,CO_2平均转动能变化增加了2.33倍;测量CO_2转动能级的多普勒增宽吸收线,得到V=14和20时,其获得的平均平动能大体随J增大而线性增大;最后,在单一碰撞条件下,测量KH(V=14~21)与CO_2(00~00,J)的振动-转动碰撞能量转移速率系数,结果显示V=19的总碰撞速率系数是V=14的4.5倍,而V>19则呈下降趋势。
The processes of vibration-rotation energy transfer between highly vibrationally excited KH(V = 14 ~ 21) and CO_2 were studied by using the pump-probe technique.KH is formed by the K(5P)+H_2 reaction.The pulse laser prepares KH in the highly vibrational levels.Energy gain into CO_2 resulting from collisions with excited KH was probed by using laser overtone spectroscopy technique.The rotational temperatures of CO_2(00~00,J = 32 ~ 48) states were obtained.The average rotational energy of the scattered CO_2 molecules is increased by a factor of 2.33 when KH level V = 14 increases to V = 21.The nascent distributions of recoil velocities for collisions were determined from stimulated absorption line profiles of individual CO_2 rotational states.The average translational energy of the scattered CO_2 molecules is increased roughly linearly as a function of CO_2 J state.Under single collision conditions,state-specific energy transfer rate coefficients for collisions of highly excited KH with CO_2 were obtained.For V = 19,the integrated rate coefficients kint increases by a factor of 4.5 to V = 14,but when V > 19,it decreases roughly.
The processes of vibration-rotation energy transfer between highly vibrationally excited KH(V = 14 ~ 21) and CO_2 were studied by using the pump-probe technique.KH is formed by the K(5P)+H_2 reaction.The pulse laser prepares KH in the highly vibrational levels.Energy gain into CO_2 resulting from collisions with excited KH was probed by using laser overtone spectroscopy technique.The rotational temperatures of CO_2(00~00,J = 32 ~ 48) states were obtained.The average rotational energy of the scattered CO_2 molecules is increased by a factor of 2.33 when KH level V = 14 increases to V = 21.The nascent distributions of recoil velocities for collisions were determined from stimulated absorption line profiles of individual CO_2 rotational states.The average translational energy of the scattered CO_2 molecules is increased roughly linearly as a function of CO_2 J state.Under single collision conditions,state-specific energy transfer rate coefficients for collisions of highly excited KH with CO_2 were obtained.For V = 19,the integrated rate coefficients kint increases by a factor of 4.5 to V = 14,but when V > 19,it decreases roughly.
引文
[1]Chang Y P,Hsiao M K,Liu D K,et al.Rotational and vibrational state distributions of NaH in the reactions of Na(4~2S,3~2D,and 6~2S)with H_2:Insertion versus harpoon-type mechanisms[J].J.Phys.Chem.,2008,128(23):234308-1/6.
[2]Bai Zhenao,Cui Xiuhua,Zhao Yikun,et al.Experimental evaluation of reactive and nonreactive cross sections in Cs(7D)+H_2 collisions[J].Chinese Journal of Quantum Electronics(量子电子学报),2008,25(6):670(in Chinese).
[3]Wang Q,Shen Y F,Dai K.Rate coefficients measurement for the energy-pooling collisions Cs(5D)+Cs(5D)→Cs(6S)+Cs(nl=9D,11S,7F)[J].Opt.Commun.,2008,281:2112-2119.
[4]Li Lin,Xin Jingtao,Liu Jing,et al.Saturation effect and velocity selective population of 5S_(1/2)→5P_(3/2)with laser excitation in Rb-H_2 vapor[J].Chinese Journal of Quantum Electronics(量子电子学报),2008,25(3):266(in Chinese).
[5]Yuan L W,Du J,Mullin A S.Energy-dependent dynamics of large-ΔE collisions:Highly vibrationally excited azulene(E~20390 and 38580 cm~(-1))with CO_2[J].J.Chem.Phys.,2008,129(1):014303-1/11.
[6]Wong T H,Kleiber P D,Yang K H.Chemical dynamics of the reaction K~*(5p~2P)+H_2→KH(v=0;J)+H:Electronic orbital alignment effects[J].J.Chem.Phys.,1999,110:6743-6748.
[7]Campargue A,Bailly D,Teffo J L,et al.The v_1+v_3 Dyad of~(12)CO_2 and~(13)CO_2[J].J.Mol.Spectrosc,1999,193:204-212.
[8]Lucchesini A,Gozzini S.Diode laser overtone spectroscopy of CO_2 at 780 nm[J].J.Quant.Spectrosc.Radiat.Transf.,2005,96:289-299.
[9]Giroud M,Nedelec O.Lifetimes and collisions in KH,A~1Σ~+,v'=5-22[J].J.Chem.Phys.,1982,77:3998-4005.
[2]Bai Zhenao,Cui Xiuhua,Zhao Yikun,et al.Experimental evaluation of reactive and nonreactive cross sections in Cs(7D)+H_2 collisions[J].Chinese Journal of Quantum Electronics(量子电子学报),2008,25(6):670(in Chinese).
[3]Wang Q,Shen Y F,Dai K.Rate coefficients measurement for the energy-pooling collisions Cs(5D)+Cs(5D)→Cs(6S)+Cs(nl=9D,11S,7F)[J].Opt.Commun.,2008,281:2112-2119.
[4]Li Lin,Xin Jingtao,Liu Jing,et al.Saturation effect and velocity selective population of 5S_(1/2)→5P_(3/2)with laser excitation in Rb-H_2 vapor[J].Chinese Journal of Quantum Electronics(量子电子学报),2008,25(3):266(in Chinese).
[5]Yuan L W,Du J,Mullin A S.Energy-dependent dynamics of large-ΔE collisions:Highly vibrationally excited azulene(E~20390 and 38580 cm~(-1))with CO_2[J].J.Chem.Phys.,2008,129(1):014303-1/11.
[6]Wong T H,Kleiber P D,Yang K H.Chemical dynamics of the reaction K~*(5p~2P)+H_2→KH(v=0;J)+H:Electronic orbital alignment effects[J].J.Chem.Phys.,1999,110:6743-6748.
[7]Campargue A,Bailly D,Teffo J L,et al.The v_1+v_3 Dyad of~(12)CO_2 and~(13)CO_2[J].J.Mol.Spectrosc,1999,193:204-212.
[8]Lucchesini A,Gozzini S.Diode laser overtone spectroscopy of CO_2 at 780 nm[J].J.Quant.Spectrosc.Radiat.Transf.,2005,96:289-299.
[9]Giroud M,Nedelec O.Lifetimes and collisions in KH,A~1Σ~+,v'=5-22[J].J.Chem.Phys.,1982,77:3998-4005.