We use cryogenic ion trap vibrational spectroscopy in combination with density functional theory to probe how the structural variability of alumina manifests itself in the structures of the gas-phase clusters (Al2 O3 )n AlO2- with n=1-6. The infrared photodissociation spectra of the D2 -tagged complexes, measured in the fingerprint spectral range (400-1200 cm-1 ), are rich in spectral features and start approaching the vibrational spectrum of amorphous alumina particles for n>4. Aided by a genetic algorithm, we find a trend towards the formation of irregular structures for larger n, with the exception of n=4, which exhibits a C3v ground-state structure. Locating the global minima of the larger systems proves challenging.

作者：Xiaowei, Song；Matias R, Fagiani；Sandy, Gewinner；Wieland, Sch?llkopf；Knut R, Asmis；Florian A, Bischoff；Fabian, Berger；Joachim, Sauer

来源：Chemphyschem : a European journal of chemical physics and physical chemistry 2017 年 18卷 8期