Electronic Spectra and Structures of Solvated NH4 Radicals, NH4(NH3)n (n = 1−8)
Electronic Spectra and Structures of Solvated NH4 Radicals, NH4(NH3)n (n = 1−8)
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溶剂化 NH4 自由基 NH4(NH3)n (n = 1−8) 的电子光谱和结构
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
K. Fuke
中科院分区：
文献类型：
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作者：
S. Nonose;T. Taguchi;Feiwu Chen;S. Iwata;K. Fuke
用激光光耗尽谱研究了氨团簇光解产生的氨化铵自由基NH_4（NH_3）_n的电子光谱。从能量为9305 ± 15 cm ~（-1）开始的振动分辨谱带被成功地归属于NH_4 NH_3。这些谱带是由NH 4的3 p 2F 2 −3s 2A 1激发产生的2 2A −1 2A跃迁。第二组开始于能量10073 ± 15 cm-1的带被指定为12 E − 12 A跃迁。一系列NH 4（NH3）n（n = 1−8）的电子光谱也在4500−16000 cm-1的能量范围内以低分辨率记录下来。当n ≥ 5时，激发能从NH_4的15062 cm ~（-1）急剧下降到NH_4（NH_3）_4的5800 cm ~（-1），而光谱无明显变化。这是由于氨团簇中NH_4的自发电离引起的。从光谱带位置确定了NH 4（NH3）n在激发态的连续结合能。
Electronic spectra of ammoniated ammonium radicals, NH4(NH3)n, produced through the photolysis of ammonia clusters, are investigated with a laser photodepletion spectroscopy. Vibrationaly resolved bands beginning at energy of 9305 ± 15 cm-1 are successfully assigned to NH4NH3. These bands are ascribed to the 2 2A −1 2A transition derived from the 3p 2F2−3s 2A1 excitation of NH4. A second group of bands beginning at energy 10073 ± 15 cm-1 is assigned to the 12E−12A transition. Electronic spectra of a series of NH4(NH3)n (n = 1−8) are also recorded with low resolution in the energy region of 4500−16000 cm-1. A drastic decrease of the excitation energy from 15062 cm-1 for NH4 to 5800 cm-1 for NH4(NH3)4 is observed, while no appreciable spectral change is found for n ≥ 5. The large spectral change is ascribed to the spontaneous ionization of NH4 in ammonia clusters. Successive binding energies of NH4(NH3)n in the excited state are determined from the spectral band positions.