Song Xiaowei, Fagiani Matias R, Gewinner Sandy, Schöllkopf Wieland, Asmis Knut R, Bischoff Florian A, Berger Fabian, Sauer Joachim
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany.
J Chem Phys. 2016 Jun 28;144(24):244305. doi: 10.1063/1.4954158.
We use cryogenic ion trap vibrational spectroscopy in combination with quantum chemical calculations to study the structure of mono- and dialuminum oxide anions. The infrared photodissociation spectra of D2-tagged AlO1-4 (-) and Al2O3-6 (-) are measured in the region from 400 to 1200 cm(-1). Structures are assigned based on a comparison to simulated harmonic and anharmonic IR spectra derived from electronic structure calculations. The monoaluminum anions contain an even number of electrons and exhibit an electronic closed-shell ground state. The Al2O3-6 (-) anions are oxygen-centered radicals. As a result of a delicate balance between localization and delocalization of the unpaired electron, only the BHLYP functional is able to qualitatively describe the observed IR spectra of all species with the exception of AlO3 (-). Terminal Al-O stretching modes are found between 1140 and 960 cm(-1). Superoxo and peroxo stretching modes are found at higher (1120-1010 cm(-1)) and lower energies (850-570 cm(-1)), respectively. Four modes in-between 910 and 530 cm(-1) represent the IR fingerprint of the common structural motif of dialuminum oxide anions, an asymmetric four-member Al-(O)2-Al ring.
我们结合量子化学计算，使用低温离子阱振动光谱来研究单铝和双铝氧化物阴离子的结构。在400至1200厘米⁻¹的区域内测量了D₂标记的AlO₁⁻⁴⁻和Al₂O₃⁻⁶⁻的红外光解离光谱。通过与从电子结构计算得出的模拟谐波和非谐波红外光谱进行比较来确定结构。单铝阴离子含有偶数个电子，并呈现电子闭壳基态。Al₂O₃⁻⁶⁻阴离子是以氧为中心的自由基。由于未成对电子的定域化和离域化之间的微妙平衡，除了AlO₃⁻之外，只有BHLYP泛函能够定性地描述所有物种的观测红外光谱。末端Al - O伸缩模式出现在1140至960厘米⁻¹之间。超氧和过氧伸缩模式分别出现在较高能量（1120 - 1010厘米⁻¹）和较低能量（850 - 570厘米⁻¹）处。910至530厘米⁻¹之间的四种模式代表了双铝氧化物阴离子常见结构 motif（一个不对称的四元Al - (O)₂ - Al环）的红外指纹。
