Journal of Physics B: Atomic, Molecular and Optical Physics ( IF 1.6 ) Pub Date : 2020-11-21 , DOI: 10.1088/1361-6455/abc142 Jiwen Guan , Tobias Sixt , Katrin Dulitz , Frank Stienkemeier
In a proof-of-principle experiment, we demonstrate that metastable nitric oxide molecules, NO(a4Π i ), generated inside a pulsed, supersonic beam, can be detected by reactive gas-phase collisions with electronically excited Li atoms in the 22P3/2 state. Since the internal energy of NO(a4Π i , v ⩽ 4) is lower than the ionization potential of Li in the 22S1/2 electronic ground state, we observe that the product ion yield arising from autoionizing NO(a4Π i ) + Li(22S1/2) collisions is a factor of 21 lower than the ion yield from NO(a4Π i ) + Li(22P3/2) collisions. We also compare our findings with measurements of relative rates for metastable N2 + Li(22S1/2) and metastable N2 + Li(22P3/2) reactive collisions. Using this detection method, we infer densities of ≈600 NO(a4Π i ) molecules/cm3 and ≈6 ⋅ 104 metastable N2 molecules/cm3 in the interaction region. Our results also allow for an estimate of the fractional population of NO(a4Π i , v ⩾ 5) prior to the collision process. The production of NO(a4Π i ) in selected vibrational states using laser excitation from the X2Π r ground state will open possibilities for the detailed study of vibrational-state-selected NO(a4Π i )–Li(22P3/2) collisions.
中文翻译:
与激光激发的锂的反应性碰撞灵敏检测亚稳NO和N 2
在一个验证的原理的实验中,我们证明了亚稳定的一氧化氮分子,NO(一4 Π我),一个脉冲,超声束的内部产生,可通过与在2电子激发Li原子的反应性气体相碰撞检测2 P 3/2状态。由于NO的内部能量(一个4 Π我,v ⩽4)是除Li在2电离电位低2 š 1/2电子基态时,我们观察到产物离子产率从自电离NO产生(一个4 Π我)+栗(2 2 š 1/2 )碰撞是比从NO离子产率21降低(一个一个因子4 Π我)+栗(2 2 P 3/2)的碰撞。我们还将我们的发现与亚稳态N 2 + Li(2 2 S 1/2)和亚稳态N 2 + Li(2 2 P 3/2)反应性碰撞的相对速率的测量结果进行比较。使用这种检测方法中,我们推断≈600NO的密度(一个4 Π我)分子/ cm 3和≈6⋅10个4亚稳Ñ 2分子/ cm 3 在互动区域。我们的结果还允许NO的分数群的估计数(a 4 Π我,v碰撞过程之前⩾5)。NO的产生(一4 Π我在使用激光激发来自X选择的振)2 Π ř基态将打开的详细研究的可能性振动状态选择的NO(一4 Π我)-Li(2 2 P 3/2)碰撞。