高振动激发态DBr（X1Σ+,v″=8、7）与 D2,Ar间的碰撞振动能量转移

Vibrational energy relaxation of highly vibrationally excited DBr（X1Σ+,v″=8、7） with D2 and Ar

利用YAG激光器泵浦OPO激光简并受激超拉曼泵浦DBr分子至基电子态的高振动态v″=8、7,研究高振动态DBr分子与其他碰撞气体(Ar、D2)的碰撞弛豫过程.对于DBr(v″=8)和Ar、D2混合体系,由高分辨瞬时激光感应荧光光谱方法探测碰撞弛豫后DBr分子振动态v″=8的时间分辨布居数的演化过程.保持总压强不变,改变碰撞气体的摩尔配比,测量相应条件下的有效寿命,由混合气体系统中Stern-Volmer公式,得到DBr(v″=8)分子与Ar、D2的碰撞弛豫速率系数分别为k8(Ar)=(0.51±0.1)×10^-12 cm^3molecule^-1s^-1,k8(D2)=(3.50±0.8)×10^-12 cm^3 molecule^-1 s^-1;DBr(v″=8)分子的平均自弛豫速率系数为k8(DBr)=(1.20±0.4)×10^-12 cm^3molecule^-1s^-1.对于摩尔配比为0.5的DBr和D2混合体系,Ti宝石激光器分别双光子激发DBr v″≤8、7各振动态至第一电子激发态A^1Πv′态,测量各个振动态的荧光光强随时间演化,测量结果表明DBr(v″=8、7)与D2的碰撞弛豫中均发生了二量子弛豫;对于摩尔配比为0.4的DBr(v″=8)和Ar混合体系,只有连续单量子碰撞弛豫过程.

Highly vibrationally excited DBr(X^1Σ^+,v″=8、7)is prepared using degenerated stimulated hyper-Raman(DSHR)excitation.Then the collisional relaxation process of excited DBr with D2(Ar)is investigated.For the DBr(v″=8)and D2(Ar)systems,High-resolution transient laser induced fluorescence(LIF)is used to detect collisionally relaxed DBr.When the total pressure remains unchanged and the molar ratio of the collision gas is changed,The effective life under corresponding conditions is measured.Based on the Stern-Volmer equation in the mixed gas system,the collision relaxation rate coefficients of DBr(v″=8)molecules with Ar,D2 are yielded,which are k8(Ar)=(0.51±0.1)×10^-12 cm^3molecule^-1s^-1 and k8(D2)=(3.50±0.8)×10^-12cm^3molecule^-1s^-1,respectively.The average self-relaxation rate coefficient of the DBr(v″=8)molecule is k8(DBr)=(1.20±0.4)×10^-12cm^3 molecule^-1s^-1.For DBr(v″=8,7)and D2 mixed systems with a molar ratio of 0.5,the Ti laser is used to probe the DBr v″≤8、7 vibration states.The decay signal of laser induced time-resolved fluorescence from A^1Π(v′)→X^1Σ^+(v″)transition is monitored.This liner region is dominated by two quantum relaxation(Δv=2)collisional propensity rules.For the mixed system of DBr(v″=8)and Ar with molar ratio of 0.4,the measurement results show that only one continuous single quantum collision relaxation(Δv=1)occurs.