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Abstract No.: MoOr-27
Speaker: Ilya N. Ioffe
Session: Gas Phase Ion Chemistry
Presentation date: Mon, Aug 28, 2006
Presentation time: 16:50 – 17:10

Mass Spectrometric, Photoelectron Spectroscopic, and Quantum Chemical Studies of Multiply Charged Anions

Ilya N. Ioffe1, Stanislav M. Avdoshenko1, Olga V. Boltalina1, Lev N. Sidorov1, Katya Berndt2, Oliver Hampe2, Andreas Eichoefer2, J. Mathias Weber2, Manfred M. Kappes2

1 Moscow State University, Moscow, Russian Federation
2 Universitaet Karlsruhe, Karlsruhe, Germany

Correspondence address: Ilya N. Ioffe, Moscow State University, Department of Chemistry, Leninskiye gory, 1, building 3, Moscow, 119992 Russian Federation.

Keywords: Affinity, Electron; Calculations, Ab Initio; Electrospray Ionization (ESI); Photodetachment.

Novel aspect: Photoelectron spectra of various multiply charged anions produced in the ESI ion source have been obtained and discussed for the first time.

 

Electrospray mass spectrometry is a convenient method of generation of multiply charged anions for subsequent gas-phase investigations. In the present work we report ESI-MS and laser photoelectron spectroscopy studies of multiply charged anions of fullerene fluorides, ligand-stabilized Cd-Se clusters, and DNA oligonucleotides. Photoelectron spectra were obtained with the use of the "magnetic bottle" spectrometer; the ion packages of the desired mass were decelerated prior to photodetachment in order to suppress the kinematic Doppler effect. Electron affinity and repulsive Coulomb barrier values of the molecules under investigation were determined. Quantum chemical DFT and TDDFT calculations were employed to interpret the electronic structure information.

Of special interest are fullerene fluorides known to exhibit rearrangement of fluorine shell even at room temperature.1 DFT calculations of the possible isomers of fluorofullerene dianions and simulation of their photoelectron spectra demonstrate that these substances are likely to isomerize under the negative ion ESI conditions towards more electron-withdrawing structures. ESI-PES also proved a convenient tool for studying the process of fullerene fluorides decomposition upon interaction with organic donors.

1. A. G. Avent and R. Taylor, Chem. Commun. 22, 2726 (2002).