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  

Resonent Vibration-Vibration Energy Transfer Between Vibrationally Excited HBr(Χ~1Σ^+ν~″=5)and H_2,N_2,CO_2,and HBr

作　　者：刘静[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10期3000-3005,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(11564039);新疆大学博士启动基金项目(BS150214)资助

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= H2,N2,CO2,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=CO2,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 N2（1←0）vibration was also observed,but it was 2orders of magnitude smaller than that of CO2.Self-relaxation rate constants of HBr（ν″=5）were measured.Single quantum relaxation accounted for about 70% of the total relaxation out of state ν″=5,and twoquantum relaxation made contributions（25%）to the vibrational relaxation at this vibrational energy.Direct evidence for 2-1resonance in HBr（ν″=5）＋H2was 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 H2 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=CO2,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= H2 and HBr was normal.For M=N2,a weak but position temperature dependence was found.It sugg

关 键 词：激光光谱 共振V-V能量转移 简并受激超拉曼泵浦 瞬时荧光测量 速率系数 HBr(ν″)振动激发态 

分 类 号：O561.5[理学—原子与分子物理]