Nitrogen bond activation is a pivotal process in chemistry, with bond excitation being fundamental to understanding the underlying mechanisms, making the preparation of molecules in specific quantum states crucial. Here we report the first overtone excitation of the N₂ molecule from X¹Σ_g⁺(v = 0, j = 0, 1, and 2) to X¹Σ_g⁺(v = 2, j = 0, 1, 2, and 3) using the stimulated Raman pumping (SRP) method in a pulsed molecular beam. N₂ was detected using 2+1 resonance-enhanced multiphoton ionization through the a″¹Σ_g⁺ state. An excitation efficiency of 4% was achieved within the excitation region in which the SRP laser intensity was saturated, indicating the low cross-sectional nature of the process. The SRP detuning spectra for different branches were measured, and the excited N₂ [X¹Σ_g⁺(v = 2)] was further used to access various vibrational states of a″¹Σ_g⁺, enabling the determination of its vibrational constants. This research opens up new opportunities for studying the specific high vibrational excitation of nitrogen in reactions and scattering experiments and contributes additional precise spectral data for the N₂ molecule.

中文翻译：

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通过受激发拉曼泵浦对氮分子进行泛音激发


氮键活化是化学中的关键过程，键激发是理解潜在机制的基础，因此制备特定量子态的分子至关重要。在这里，我们报告了在脉冲分子束中使用受激拉曼泵浦 （SRP） 方法，N₂ 分子从 X¹Σ_g⁺（v = 0， j = 0、1 和 2）到 X¹Σ_g⁺（v = 2， j = 0、1、2 和 3）的第一个泛音激发。使用 2+1 共振增强多光子电离通过 a“¹Σ_g⁺ 状态检测 N₂。在 SRP 激光强度饱和的激发区域内实现了 4% 的激发效率，表明该工艺的低横截面性质。测量了不同分支的 SRP 失谐光谱，并进一步使用激发的 N₂ [X¹Σ_g⁺（v = 2）] 来获得 a“¹Σ_g⁺ 的各种振动状态，从而能够确定其振动常数。这项研究为研究反应和散射实验中氮的特异性高振动激发开辟了新的机会，并为 N₂ 分子提供了额外的精确光谱数据。