Structural assignment of small silver clusters

May 18, 2016, 2:45 PM
8h 15m



Mr Johan VAN DER TOL (KU Leuven)Mrs dewei JIA (KU Leuven)


Johan van der Tol, Dewei Jia, Yejun Li, Valeriy Chernyy, Joost Bakker, Minh Nguyen, Ewald Janssens

Silver clusters composed of a few atoms are very interesting for photography and redox catalysis. This is mainly because of their size dependent optical properties and a strong interplay between their geometric and electronic structure, which has a discrete density of states.

Despite the wide interest in small silver clusters, there is so far, besides for Ag₃ and Ag₄ [1], no definitive (experimental) assignment of their geometry.

Ion-mobility measurements on cationic silver clusters in the gas phase are available [2], but those measurements only provide cross sections. In addition, optical absorption spectra of Ag₄ to Ag₁₄ have been recorded, mapping their electronic excited states [3].

We have recorded the infrared multiphoton dissociation (IR-MPD) spectra of Ag₃⁺ to Ag₁₂⁺, by using a Free-electron laser in the far infrared (100-200 cm⁻¹ spectroscopic wavenumbers). The silver clusters were produced in a laser vaporization cluster source and tagged with weakly bound argon, with Arₙ up to n=4, which is released after resonant photon absorption.

Comparison of calculated vibrational spectra for different structural isomers by density functional theory with the experimental IR-MPD spectra allows to determine the structures of the silver clusters. Meanwhile, the effect of Ar attachment on the smallest clusters( Ag₂⁺,Ag₃⁺, Ag₄⁺) was measured and calculated.

[1] A. Fielicke et al. J. Phys. Chem. A 110, 8060 (2006)

[2] P. Weis et al. Chem. Phys. Lett. 355, 355(2002)

[3] Harb et al. J. Chem. Phys. 129, 194108 (2008)

Primary authors

Mr Johan VAN DER TOL (KU Leuven) Mrs dewei JIA (KU Leuven)


Ewald JANSSENS (KUL) Dr Joost BAKKER (Radboud University Nijmegen) Prof. Minh Tho NGUYEN (KU Leuven Afdeling Kwantumchemie en Fysicochemie) Mr Valeriy CHERNYY (Radboud University Nijmegen) Mr Yejun Li (Solid State Physics and Magnetism Section, KULeuven)

Presentation materials