Volume 8, Issue 8 p. 1236-1239
Article

A Combined Experimental and Computational Study on the Ionization Energies of the Cyclic and Linear C3H Isomers

Ralf I. Kaiser Prof.

Ralf I. Kaiser Prof.

University of Hawaii at Manoa, Department of Chemistry, Honolulu, HI 96822, USA, Fax: (+1) 808-956-5908

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Leonid Belau Dr.

Leonid Belau Dr.

Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

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Stephen R. Leone Prof.

Stephen R. Leone Prof.

Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

Department of Chemistry and Physics, University of California, Berkeley, CA, 94720, USA

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Musahid Ahmed Dr.

Musahid Ahmed Dr.

Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

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Yimin Wang Dr.

Yimin Wang Dr.

Department of Chemistry

Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, GA 30322, USA

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Bastiaan J. Braams Dr.

Bastiaan J. Braams Dr.

Department of Mathematics and Computer Science, Emory University, Atlanta, GA 30322, USA

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Joel M. Bowman Prof.

Joel M. Bowman Prof.

Department of Chemistry

Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, GA 30322, USA

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First published: 22 May 2007
Citations: 30

Graphical Abstract

Interstellar isomers: The ionization potentials of linear and cyclic tricarbon hydride radicals (C3H) were determined for the first time. By recording photoionization efficiency curves and simulating the experimental spectrum (see picture), ionization potentials of the two isomers were derived. These data are of crucial importance in astrochemical models simulating the chemical evolution of the interstellar medium.

Abstract

For the first time, two hydrogen-deficient hydrocarbon radicals are generated in situ via laser ablation of graphite and seeding the ablated species in acetylene gas, which acts as a carrier and reactant simultaneously. By recording photoionization efficiency curves (PIE) and simulating the experimental spectrum with computed Franck–Condon (FC) factors, we can reproduce the general pattern of the PIE curve of m/z=37. We recover ionization energies of 9.15 eV and 9.76 eV for the linear and cyclic isomers, respectively. Our combined experimental and theoretical studies provide an unprecedented, versatile pathway to investigate the ionization energies of even more complex hydrocarbon radicals in situ, which are difficult to prepare by classical synthesis, in future experiments.