Kreckel Holger, Bing Dennis, Reinhardt Sascha, Petrignani Annemieke, Berg Max, Wolf Andreas
Max-Planck-Institut fur Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
J Chem Phys. 2008 Oct 28;129(16):164312. doi: 10.1063/1.2994730.
We have performed chemical probing spectroscopy of H(3) (+) ions trapped in a cryogenic 22-pole ion trap. The ions were buffer gas cooled to approximately 55 K by collisions with helium and argon. Excitation to states above the barrier to linearity was achieved by a Ti:sapphire laser operated between 11 300 and 13 300 cm(-1). Subsequent collisions of the excited H(3) (+) ions with argon lead to the formation of ArH(+) ions that were detected by a quadrupole mass spectrometer with high sensitivity. We report the observation of 17 previously unobserved transitions to states above the barrier to linearity. Comparison to theoretical calculations suggests that the transition strengths of some of these lines are more than five orders of magnitude smaller than those of the fundamental band, which renders them-to the best of our knowledge-the weakest H(3) (+) transitions observed to date.
我们对捕获在低温22极离子阱中的H₃⁺离子进行了化学探测光谱研究。通过与氦气和氩气碰撞，离子被缓冲气体冷却至约55K。使用工作在11300至13300cm⁻¹之间的钛宝石激光器将离子激发到高于线性势垒的状态。随后，激发态的H₃⁺离子与氩气碰撞导致形成ArH⁺离子，这些离子由具有高灵敏度的四极质谱仪检测。我们报告了观察到17个先前未观察到的到高于线性势垒状态的跃迁。与理论计算的比较表明，其中一些谱线的跃迁强度比基频带的跃迁强度小五个数量级以上，据我们所知，这使得它们成为迄今为止观察到的最弱的H₃⁺跃迁。
