Four C₂H₄N₄ structural isomers are investigated with fs laser-induced breakdown spectroscopy. Plasma emissions, C I, H_α, the CN violet system (B²Σ⁺–X²Σ⁺, Δν = 0 sequence) and C₂ swan system (d³Π_g–a³Π_u, Δν = 0 sequence) are measured. The temporal evolution of the characteristic emission intensity is obtained for each emission and their lifetimes are calculated. The lifetimes of the molecular emissions are much longer than those of the atomic emissions. Characteristic emission intensities and lifetime are correlated with the molecular structures of the four isomers to a certain extent. Plasma temperature is extracted by fitting the spectrum of the CN violet system, B²Σ⁺–X²Σ⁺; Δν = 0 sequence, and is weakly correlated with the molecular structures of the four isomers. Using the characteristic emission intensities as input, principal component analysis (PCA) and artificial neural network (ANN) analysis are performed and the individual isomers can be well identified with PCA or ANN.

中文翻译：

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使用fs激光诱导击穿光谱法鉴定C2H4N4结构异构体。

用fs激光诱导击穿光谱研究了四种C ₂ H ₄ N ₄结构异构体。等离子体排放，CI，H _α时，CN紫体系（B ² Σ ⁺ -X ² Σ ⁺，Δ ν = 0的序列）和c ^ ₂天鹅系统（d ³ Π_克-a ³ Π _ü，Δ ν= 0序列）进行测量。获得每种发射的特征发射强度的时间演变，并计算其寿命。分子发射的寿命比原子发射的寿命长得多。特征发射强度和寿命在一定程度上与四种异构体的分子结构相关。等离子体温度由拟合CN紫色系统的频谱中提取，B ² Σ ⁺ -X ² Σ ⁺ ; Δ ν= 0序列，并且与四个异构体的分子结构弱相关。使用特征发射强度作为输入，执行主成分分析（PCA）和人工神经网络（ANN）分析，并且可以使用PCA或ANN很好地识别各个异构体。