光学一光学双共振激发NaK至61∑+高位电子态,研究了NaK(61∑+)与H2的电子一振转能量转移。利用相干反斯托克斯拉曼散射(CARS)光谱技术检测H2的振转态分布。扫描CARS谱表明H2在(1,1),(2,1),(2,2),(2,3),(3,1),(3,2),(3,3)和(3,5)振转能级上有布居。对于(3,1),(3,2),(3,3)和(3,5)能级,扫描CARS谱峰值直接给出布居数之比。对于(1,1),(2,1),(2,2)和(2,3)能级,扫描CARS谱峰值给出二个可能的布居数之比,利用一个速率方程组,由时间分辨CARS轮廓可以得到真实的比值。用n1-~ns分别表示Hz的(3,1),(2,1),(1,1),(3,3),(2,3),(2,2),(3,2)和(3,5)能级上布居密度,得到m/n1~n8/n1分别为0.51,0.97,0.45,0.18,0.10,0.26和0.31。利用Stem-Volmer公式,得到6’乏’态的总退布速率系数为(2.1±0.4)×10^-10cm^3s^-1,由H2各振转能级布居数之比,得到61∑+-(1,1),(2,1),(2,2),(2,3),(3,1),(3,2),(3,3)和(3,5)转移速率系数(10^-11cm^3·s^-1单位)分别为5.4±1.6,2.8±0.8,0.6±0.2,1.0±0.3,5.6±1.7,1.4±0.4,2.5±0.8和1.7±0.5。
The electronic to rovibrational energy transfer between the high-lying 61∑+ state of NaK and H2 was investigated. The 61∑+ state was excited using the optical-optical double resonance technique. Radiative processes were monitored by fluores- cence from the61∑+ state to the ground 11∑+ state. The CARS (coherent anti-Stokes Raman scattering) spectral technique was used to probe the internal state distribution of collisionally-populated H2 molecules. The scanned CARS spectra reveal that dur- ing E-V, R energy transfer processes H2 molecules are produced at v=1, 2 and 3 levels. The semilog plot of the time-resolved H2 (3, 1) CARS intensity was obtained at a pressure of 4X 104 Pa of Hz. The slop yields an effective quenching rate of 8. 09× 10^5 s^-1. Analogically, for (3, 2), (3, 3) and (3, 5) levels, the quenching rates are 6. 11×10^5 , 4. 32×105 and 2. 45×10s s-1 , respectively. For (3, 1), (3, 2), (3, 3) and (3, 5) levels, the population ratios were obtained from scanned CARS spectral peaks. For (1, 1), (2, 1), (2, 2) and (2,3) levels, from scanned CARS spectral peaks two possible population ratios were yielded. Through shape simulations of time resolved CARS profiles under a kinetic model the actual population ratios were deter- mined. The n2/n1, n3/n1, n4/n1, n5/n1, n6/n1, n1/n1 and ns/n1 are 0.51, 0. 97, 0. 45, 0.18, 0. 10, 0. 26 and 0. 31, where nx, n2, n3, n4, n5, n6, n7 andn8 represent the number densities of H2 at (3, 1), (2, 1), (1, 1), (3, 3), (2, 3), (2, 2), (3, 2) and (3,5) levels, respectively. The H2 molecules produced by energy transfer process were populated by 26 % at the v= 1 level, 21% at v=2 and 53% at v=3. The major vibrational energy [-(9.0±2.7)× 103 cm-1] release and the minor rotational energy [(3. 9±1.1)× 102 em 1] release are showrL Based on the Stern-Volmer equation, the radiative lifetime is (5.0±1. 3) ns for the 61∑+ state, the total rate coefficient for deactivati