Two-color (1 + 1′) zero-electron-kinetic-energy (ZEKE) and photoionization efficiency (PIE) spectra are reported via different levels in the S₁ ← S₀ (${\tilde{A}}^1{A}_2\leftarrow {\tilde{X}}^1{A}_1$) one-photon transition of jet-cooled N-methylpyrrole. The laser radiation is produced using two dye lasers, one with an 1800 l/mm grating and one with 2400 l/mm. We report spectra where the excitation and ionization radiation are produced with both combinations of the dye lasers; these spectra differ markedly. This is attributed to Wood’s anomalies with the 2400 l/mm grating: one aspect is a loss in light intensity over a range of wavelengths, attributed to a resonance anomaly. Another is the appearance of a “shadow” ZEKE spectrum and PIE curve at apparently higher ionization wavenumbers; under some conditions, a third ZEKE spectrum was observed—these latter observations arise from higher-order dispersion effects, likely caused by a Rayleigh anomaly. We comment on these observations and report more representative ZEKE and PIE spectra than those presented in a recent paper by our group [A. R. Davies, D. J. Kemp, and T. G. Wright, J. Chem. Phys. 154, 224305 (2021)] for four intermediate S₁ levels.

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评论“N-甲基吡咯中的电子、振动和扭转耦合：基态、第一激发态和阳离子态”[J. 化学 物理。154, 224305 (2021)]

通过 S ₁ ← S ₀ (${\widetilde{\mathrm{一种}}}^1{\mathrm{一种}}_2\leftarrow {\tilde{X}}^1{\mathrm{一种}}_1$) 喷射冷却N 的单光子跃迁-甲基吡咯。使用两台染料激光器产生激光辐射，一台配备 1800 l/mm 光栅，另一台配备 2400 l/mm。我们报告了用染料激光器的两种组合产生激发和电离辐射的光谱；这些光谱明显不同。这归因于伍德对 2400 l/mm 光栅的异常：一方面是由于共振异常导致的光强度在一定波长范围内的损失。另一个是在明显更高的电离波数下出现“阴影”ZEKE 谱和 PIE 曲线；在某些条件下，观察到了第三个 ZEKE 光谱——后面的这些观察来自高阶色散效应，可能是由瑞利异常引起的。我们对这些观察结果发表评论，并报告了比我们小组最近的一篇论文 [AR Davies、DJ Kemp 和 TG Wright、J. Chem. 物理。154 , 224305 (2021)] 四个中间 S ₁水平。