HBr(X~1Σ~+ν~″=5)分子与H_2,N_2,CO_2和HBr间的近共振振动-振动能量转移
|
摘要
利用简并受激超拉曼泵浦激发HBr(Χ~1Σ~+ν~″=5)振动态,由高分辨瞬时激光感应荧光(LIF)探测碰撞弛豫后HBr(ν~″≤5)各振动态时间分辨布居数的演化过程,得到了HBr(ν~″=5)分别与分子M(H_2,N_2,CO_2和HBr)的碰撞弛豫速率系数。对于M=CO_2,近共振的1-1振动-振动(V-V)能量转移是有效的,这一结果表明CO_2强的红外振动模对近共振V-V能量转移是有利的。而红外禁戒跃迁的N_2(0-1)的近共振V-V转移虽然也能观察到,但相应速率系数比CO_2小2个量级。碰撞分子的振动跃迁红外活性越强,能量转移速率系数越大。在HBr(ν~″=5)+HBr的自弛豫过程中,单量子弛豫率占总弛豫率的70%,而双量子弛豫约占25%。在HBr(ν~″=5)+H_2中,只有2-1的V-V近共振过程是重要的。同时还研究了V-V近共振能量转移速率系数与温度变化的关系,对于CO_2的1-1近共振,V-V能量转移速率系数随温度的增加而减小;对于H_2和HBr,其弛豫速率系数随温度的增加而增加;对于N_2,其弛豫速率系数随温度的增加而缓慢增加。
Collisional deactivation rate constants,k5(M)for HBr(Χ~1Σ~+ν~″=5)by M= H_2,N_2,CO_2,and HBr were obtained using the degenerated stimulated hyper-Raman(OSHR)pumping method in a pumping-probe configuration.High-resolution transient laser induced fluorescence(LIF)was used to detect collisionally relaxed HBr.For M=CO_2,an efficient near-resonant1-1vibration-to-vibration(V-V)energy exchange was observed.It appeared that the presence of a strong infrared-active vibrational mode was a favorable situation for an efficient V-Venergy transfer.A 1-1resonance exciting the infrared forbidden N_2(1←0)vibration was also observed,but it was 2orders of magnitude smaller than that of CO_2.Self-relaxation rate constants of HBr(ν~″=5)were measured.Single quantum relaxation accounted for about 70% of the total relaxation out of stateν~″=5,and twoquantum relaxation made contributions(25%)to the vibrational relaxation at this vibrational energy.Direct evidence for 2-1resonance in HBr(ν~″=5)+H_2was observed.Initial preparation of HBr(ν~″=5)resulted in nearly no population in HBr(ν~″=4),but direct population of HBr(ν~″=3).Therefore only 2-1resonant energy transfer was important for H_2 relaxation.The state specific rate constant for HBr was obtained by the analysis of the state-to-state relaxation data.It was found that the data could be fitted with one adjustable normaligation parameter using a single-quantum relaxation model,which restricted the rate constant.A strong mass effect on the vibrational relaxation rate constant was observed.A further check of the character of the V-V resonant energy transfer in highly vibrationally excited HBr was the temperature dependence of the rate constants.For M=CO_2,the temperature dependence of the 1-1near-resonant energy transfer rate constats was found to be inverted.In contranst,the temperature dependence of the relaxation rate constants for M= H_2 and HBr was normal.For M=N_2,a weak but position temperature dependence was found.It suggested that this resonance occurred by a different mechanism compared with that in CO_2.
Collisional deactivation rate constants,k5(M)for HBr(Χ~1Σ~+ν~″=5)by M= H_2,N_2,CO_2,and HBr were obtained using the degenerated stimulated hyper-Raman(OSHR)pumping method in a pumping-probe configuration.High-resolution transient laser induced fluorescence(LIF)was used to detect collisionally relaxed HBr.For M=CO_2,an efficient near-resonant1-1vibration-to-vibration(V-V)energy exchange was observed.It appeared that the presence of a strong infrared-active vibrational mode was a favorable situation for an efficient V-Venergy transfer.A 1-1resonance exciting the infrared forbidden N_2(1←0)vibration was also observed,but it was 2orders of magnitude smaller than that of CO_2.Self-relaxation rate constants of HBr(ν~″=5)were measured.Single quantum relaxation accounted for about 70% of the total relaxation out of stateν~″=5,and twoquantum relaxation made contributions(25%)to the vibrational relaxation at this vibrational energy.Direct evidence for 2-1resonance in HBr(ν~″=5)+H_2was observed.Initial preparation of HBr(ν~″=5)resulted in nearly no population in HBr(ν~″=4),but direct population of HBr(ν~″=3).Therefore only 2-1resonant energy transfer was important for H_2 relaxation.The state specific rate constant for HBr was obtained by the analysis of the state-to-state relaxation data.It was found that the data could be fitted with one adjustable normaligation parameter using a single-quantum relaxation model,which restricted the rate constant.A strong mass effect on the vibrational relaxation rate constant was observed.A further check of the character of the V-V resonant energy transfer in highly vibrationally excited HBr was the temperature dependence of the rate constants.For M=CO_2,the temperature dependence of the 1-1near-resonant energy transfer rate constats was found to be inverted.In contranst,the temperature dependence of the relaxation rate constants for M= H_2 and HBr was normal.For M=N_2,a weak but position temperature dependence was found.It suggested that this resonance occurred by a different mechanism compared with that in CO_2.
引文
[1]Strekalov M L.Chem.Phys.Lett.,2006,431(11):1.
[2]Havey D K,Liu Q,Li Z.J.Phys.Chem.A,2007,111(51):13321.
[3]Watanabe S S,Fujii H,Kohguchi H,et al.J.Phys.Chem.A,2008,112:9290.
[4]Liu C L,Hsu C H,Hsu Y C,et al.J.Chem.Phys.,2008,128:124320.
[5]Hsu C H,Liu C L,Hsu Y C,et al.J.Chem.Phys.,2008,129:044301.
[6]Havey D K,Du J,Liu Q N,et al.J.Phys.Chem.A,2010,114:1569.
[7]Du J,Sassin N A,Havey D K,et al.J.Phys.Chem.A,2013,117:12104.
[8]Yamasaki K,Fujii H,Watanabe S,et al.Phys.Chem.Chem.Phys.,2006,8:1936.
[9]Wang S Y,Zhang B,Zhu D H,et al.Spectrochim.Acta A,2012,96:517.
[10]Liu J,Shen Y F,and Dai K.Chem.Phys.,2013,425(11):62.
[11]Fedorov D A,Derevianko A,Varganov S A.J.Chem.Phys.,2014,140:184315.
[12]Jongma R T,and Wodtke A M.J.Chem.Phys.,1999,111:10957.
[13]Lawrence W G,Marter T A V,Nowlin M L,et al.J.Chem.Phys.,1997,106:127.
[14]Frerichs H,Lenzer T,Luther K.Phys.Chem.Chem.Phys.,2005,7(4):620.
[15]Alghazi A,Liu J,Dai K,et al.Chem.Phys.,2015,448:76.
[16]Mu B X,Cui X H,Shen Y F,et al.Spectrochim.Acta A,2015,148:299.
[17]Kabir M H,Antonov I O,Heaven M C.J.Chem.Phys.,2009,130:074305.
[18]Kabir M H,Antonov I O,Merritt J M,et al.J.Phys.Chem.A,2010,114:11109.
[19]Yang X M,Kim E H,Wodtke A M.J.Chem.Phys.,1992,96:5111.
[20]Flynn G W,Parmenter C S,Wodtke A M.J.Phys.Chem.,1996,100(31):12817.
[21]Mack J A,Mikulecky K,and Wodtke A M.J.Chem.Phys.,1996,105:4105.
[2]Havey D K,Liu Q,Li Z.J.Phys.Chem.A,2007,111(51):13321.
[3]Watanabe S S,Fujii H,Kohguchi H,et al.J.Phys.Chem.A,2008,112:9290.
[4]Liu C L,Hsu C H,Hsu Y C,et al.J.Chem.Phys.,2008,128:124320.
[5]Hsu C H,Liu C L,Hsu Y C,et al.J.Chem.Phys.,2008,129:044301.
[6]Havey D K,Du J,Liu Q N,et al.J.Phys.Chem.A,2010,114:1569.
[7]Du J,Sassin N A,Havey D K,et al.J.Phys.Chem.A,2013,117:12104.
[8]Yamasaki K,Fujii H,Watanabe S,et al.Phys.Chem.Chem.Phys.,2006,8:1936.
[9]Wang S Y,Zhang B,Zhu D H,et al.Spectrochim.Acta A,2012,96:517.
[10]Liu J,Shen Y F,and Dai K.Chem.Phys.,2013,425(11):62.
[11]Fedorov D A,Derevianko A,Varganov S A.J.Chem.Phys.,2014,140:184315.
[12]Jongma R T,and Wodtke A M.J.Chem.Phys.,1999,111:10957.
[13]Lawrence W G,Marter T A V,Nowlin M L,et al.J.Chem.Phys.,1997,106:127.
[14]Frerichs H,Lenzer T,Luther K.Phys.Chem.Chem.Phys.,2005,7(4):620.
[15]Alghazi A,Liu J,Dai K,et al.Chem.Phys.,2015,448:76.
[16]Mu B X,Cui X H,Shen Y F,et al.Spectrochim.Acta A,2015,148:299.
[17]Kabir M H,Antonov I O,Heaven M C.J.Chem.Phys.,2009,130:074305.
[18]Kabir M H,Antonov I O,Merritt J M,et al.J.Phys.Chem.A,2010,114:11109.
[19]Yang X M,Kim E H,Wodtke A M.J.Chem.Phys.,1992,96:5111.
[20]Flynn G W,Parmenter C S,Wodtke A M.J.Phys.Chem.,1996,100(31):12817.
[21]Mack J A,Mikulecky K,and Wodtke A M.J.Chem.Phys.,1996,105:4105.