The protonated oxygen molecule, O₂H⁺, and its helium complex, He-O₂H⁺, have been investigated by vibrational action spectroscopy in a cryogenic 22-pole ion trap. For the He-O₂H⁺ complex, the frequencies of three vibrational bands have been determined by predissociation spectroscopy. The elusive O₂H⁺ has been characterized for the first time by high-resolution rovibrational spectroscopy via its ν₁ OH-stretching band. Thirty-eight rovibrational fine structure transitions with partly resolved hyperfine satellites were measured (56 resolved lines in total). Spectroscopic parameters were determined by fitting the observed lines with an effective Hamiltonian for an asymmetric rotor in a triplet electronic ground state, ${\tilde{X}}^3{A}^{\prime \prime }$, yielding a band origin at 3016.73 cm⁻¹. Based on these spectroscopic parameters, the rotational spectrum is predicted, but not yet detected.

中文翻译：

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低温离子阱中O2H +的高分辨率红外光谱

质子化的氧分子O ₂ H ⁺及其氦配合物He-O ₂ H ⁺已通过振动作用光谱法在22极低温离子阱中进行了研究。对于He-O ₂ H ⁺络合物，通过预离解光谱法确定了三个振动带的频率。难以捉摸Ò ₂ ħ ⁺已由高分辨率振转光谱经由其特征在于，第一次ν ₁OH拉伸带。测量了38个具有部分分辨的超精细卫星的振动精细结构转换（共计56条分辨线）。通过在三重态电子基态下对非对称转子的有效哈密顿量拟合观察到的谱线，确定光谱参数。${\tilde{X}}^3{\mathrm{一个}}^{\prime \prime }$，在3016.73 cm ^-1处产生谱带原点。基于这些光谱参数，预测了旋转光谱，但尚未检测到。