Rb-H2 mixture was irradiated with pulses of 696.4 nm radiation from a OPO laser, populating 6D state by two-photon absorption. The vibrational levels of RbH(X1∑+,v"=0~2) generated in the reaction of Rb(6D) with H2. Vibrational-state-specific total-removal relaxation rate coefficients, kv(M), for RbH(X1∑+,v"=15~22) by M=H2 and N2 were investigated in a pump and probe configuration. By the overtone pumping with a cw diode laser, highly vibrational states v =15~22 of RbH in its ground electronic state were obtained. Another diode laser was used to probe the prepared vibrational state. The decay signal of laser induced time-resolved fluorescence from A1∑+ (v')→X1∑+(v") transition was monitored. Based on the Stern-Volmer e-quation, the total relaxation rate coefficient kv ( H2) were yielded. A plot of kv ( H2 + N2) vsai mole fraction H2) yields a line with a slope of kv(H2)-kv(N2) and an intercept of kv(N2). The values of kv(H2) obtained from the slope of the fitted lines compare well with determined values of the kv(H2) from the Sern-Volmer plots. At v"<18, the rate coefficients kv(M) increases linearly with vibrational quantum number. This linear region is dominated by single quantum relaxation (Ai/=1) collisional propensity rules. The region (v"≥18) where the dependence is much stronger than linear shows significant contribution from multiquantum (△μ≥2) relaxation or resonant vibration-vibration energy transfer between highly vibrationally excited RbH and H2 or N2. For RbH(v")+N2(0), we measured the time-profile of v"=16 after preparation of v" = 21. A clear bimodal distribution was observed. The first peak is due to resonant vibration-vibration energy transfer; RbH(v"=21) + N2(0)→RbH(v"=16) + N2(l). The much broader second peak, at longer time delays, is due to sequential single-quantum relaxation. Although the second process results in a distribution that is much more spread out in time, the peak height is in the same order of magnitude, indicating that the two processes are at least comparable in probability.%脉冲激光激发Rb原子至6D态,Rb(6D)与H2反应生成RbH(X1Σ+,v″=0～2)振动态.研究了RbH(X1Σ+)高位振动态与H2,N2间的碰撞弛豫过程,利用泛频泵浦分别激发X1Σ+(v″=0)至X1Σ+(v″=15～22)各振动态,检测激光激发X1Σ+(v′)至A1Σ+(v′),测量A1Σ+(v′)的时间分辨激光感应荧光光谱,利用Stern-Volmer方程,得到振动能级v″的总的弛豫速率系数kv(H2).在H2和N2的混合气体中,总弛豫速率系数kv(H2+N2)与α(H2的摩尔配比)成直线的关系,其斜率为kv(H2)-kv(N2),而截距为kv(N2).对于v″＜18主要发生单量子弛豫(Δv=1)过程,kv(H2)和kv(N2)与振动量子数v″均成线性增加关系.对于v″≥18,多量子弛豫(Δv≥2)过程及共振振动-振动转移起重要作用.对于RbH(v″=21)+N2(0),测量v″=16的布居数时间演化轮廓,在20 μs内有一个锐锋,在100～200 μs内有一个较低的宽峰,锐锋相应于RbH(v″=21)+ N2(0)→RbH(v″=16)+N2(1)的共振转移过程,而宽峰是由相继的单量子过程产生的.
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