Abstract Electron energy-loss spectra were measured in isoxazole in the excitation energy range 3.5-10 eV to investigate the valence excited states. Spectra recorded at different scattering conditions enabled the identification of the singlet and triplet states and the determination of their vertical excitation energies. The two lowest energy triplet bands, ππ* 13A' and ππ* 23A' at 4.20 and 5.30 eV, respectively show vibrational progressions. The first triplet state, 15a'π* 13A'' that involves excitation from the nitrogen lone-pair orbital is observed at 5.68 eV. The three singlet valence states, ππ* 11A', nNπ* 11A'' and ππ* 21A' are observed at 5.96, 6.49 and 6.88 eV, respectively in accord with the absorption measurements. Resonance excitation of the triplet and singlet states was noticed.

中文翻译：

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用电子能量损失谱研究异恶唑分子的激发态

摘要 在异恶唑中在 3.5-10 eV 的激发能范围内测量电子能量损失谱以研究价激发态。在不同散射条件下记录的光谱能够识别单线态和三线态并确定它们的垂直激发能量。两个最低能量三重带，ππ* 13A' 和 ππ* 23A' 在 4.20 和 5.30 eV，分别显示了振动进程。第一个三重态 15a'π* 13A'' 涉及来自氮孤对轨道的激发，在 5.68 eV 处观察到。根据吸收测量结果，分别在 5.96、6.49 和 6.88 eV 处观察到三个单线态价态 ππ* 11A'、nNπ* 11A'' 和 ππ* 21A'。注意到三重态和单重态的共振激发。