title: Dianions of 7,7,8,8-tetracyano-p-quinodimethane and perfluorinated tetracyanoquinodimethane: information on excited states from lifetime measurements in an electrostatic storage ring and optical absorption spectroscopy.
abstract: We have developed an experimental technique that allows us to study the physics of short lived molecular dianions in the gas phase. It is based on the formation of monoanions via electrospray ionization, acceleration of these ions to keV energies, and subsequent electron capture in a sodium vapor cell. The dianions are stored in an electrostatic ion storage ring in which they circulate with revolution times on the order of 100 micros. This enables lifetime studies in a time regime covering five orders of magnitude, 10(-5)-1 s. We have produced dianions of 7,7,8,8-tetracyano-p-quinodimethane and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane (TCNQ-F(4)) and measured their lifetimes with respect to electron autodetachment. Our data indicate that most of the dianions were initially formed in electronically excited states in the electron transfer process. Two levels of excitation were identified by spectroscopy on the dianion of TCNQ-F(4), and the absorption spectrum was compared with spectra obtained from spectroelectrochemistry of TCNQ-F(4) in acetonitrile solution.
authors: Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark.
authors: Subhasis
authors: S
authors: Panja
authors: Umesh
authors: U
authors: Kadhane
authors: Jens Ulrik
authors: JU
authors: Andersen
authors: Anne I S
authors: AI
authors: Holm
authors: Preben
authors: P
authors: Hvelplund
authors: Maj-Britt Suhr
authors: MB
authors: Kirketerp
authors: Steen Brondsted
authors: SB
authors: Nielsen
authors: Kristian
authors: K
authors: Stochkel
authors: Robert N
authors: RN
authors: Compton
authors: James S
authors: JS
authors: Forster
authors: Kristine
authors: K
authors: Kilså
authors: Mogens Brondsted
authors: MB
authors: Nielsen