Electronic Spectra of Corannulenic Cations and Neutrals in Neon Matrices and Protonated Corannulene in the Gas Phase at 15 K
Electronic Spectra of Corannulenic Cations and Neutrals in Neon Matrices and Protonated Corannulene in the Gas Phase at 15 K
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15K 气相中氖基体和质子化 Corannulenic 阳离子和中性子的电子光谱
DOI：
10.1515/zpch-2015-0598
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
J. Maier
中科院分区：
文献类型：
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作者：
C. Rice;J. Fulara;I. Garkusha;Á. Nagy;F.;Oliver Gause;J. Maier
摘要在热阴极离子源中，由corannulene蒸气产生的m/z = 250的质量选择离子沉积后，在6 K氖基质中检测到624.1，601.2和590.0nm的三个吸收系统。后两个系统也观察到中性corannulene在固体氖与伴随轰击的矩阵与氩离子的沉积后。吸收光谱中的特征分别归属于环丁二烯基苯并[ghi]荧蒽阳离子的42 A“”<$X2A“跃迁和两种碗状corannulene阳离子的32A”<$X2A "和32A“<$X2A”跃迁。分配是基于用SAC-CI和CASPT 2方法计算的激发能。质子化corannulene的电子吸收光谱在氖基质中在515.1和398.8 nm处具有起始点，随后沉积由corannulene与EtOH 2+反应产生的质量选择束。根据理论预测，吸收被分配给3，41 A ← X1 A跃迁。电子光谱也记录在气相中使用共振多光子碎裂技术在离子阱在振动和旋转温度为15 K。在521 ± 1 nm和396.4 ± 0.1 nm处观察到3，41 A ← X1 A跃迁。31 A激发态的电子寿命为10.5 fs，而41 A激发态的电子寿命为10.2 ps。在41 A ← X1 A跃迁中可以辨别出一种独特的振动模式。
Abstract Three absorption systems starting at 624.1, 601.2, and 590.0 nm were detected in a 6 K neon matrix following deposition of mass selected m/z = 250 ions produced from corannulene vapour in a hot cathode ion source. The two latter systems were also observed after deposition of neutral corannulene in solid neon with concomitant bombardment of the matrix with argon ions. The features in the absorption spectrum are assigned to the 42A′′ ← X2A′′ transition of cylobutadieno-benzo[ghi]fluoranthene cation and to the 32A′ ← X2A′′ and 32A′′ ← X2A′ transitions of two Jahn-Teller structures of bowl-shaped corannulene cations, respectively. The assignment is based on excitation energies calculated with the SAC-CI and CASPT2 methods. The electronic absorption spectrum of protonated corannulene has onsets at 515.1 and 398.8 nm in a neon matrix, following deposition of a mass-selected beam produced by reactions of corannulene with EtOH2+. The absorptions are assigned, on the basis of theoretical predictions, to the 3,41A ← X1A transitions. The electronic spectrum was also recorded in the gas phase using a resonant multiphoton fragmentation technique in an ion trap at vibrational and rotational temperatures of 15 K. The 3,41A ← X1A transitions are observed with origin bands at 521 ± 1 nm and 396.4 ± 0.1 nm. The 31A excited electronic state indicates fast internal conversion of ≈ 5 fs, while the 41A state has a lifetime of ≈ 0.2 ps. A distinct vibrational pattern is discernible in the 41A ← X1A transition.