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Journal ArticleDOI

Fragment kinetic energy distributions in ion induced CO2 fragmentation

05 Nov 2012-Vol. 388, Iss: 10, pp 102019

AbstractThe dissociation of CO3+2 formed in heavy ion induced ionization of CO2 has been studied using the technique of time of flight mass spectroscopy with position sensitive ion detector, with 5 MeV/u Si12+ ions as projectiles. The kinetic energy released in the CO3+2→ C+ + O+ + O+ is measured and compared to theoretical ab initio calculations as well as photoionization results.

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References
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Journal ArticleDOI
TL;DR: A description of the ab initio quantum chemistry package GAMESS, which can be treated with wave functions ranging from the simplest closed‐shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication.
Abstract: A description of the ab initio quantum chemistry package GAMESS is presented. Chemical systems containing atoms through radon can be treated with wave functions ranging from the simplest closed-shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication. Emphasis is given to novel features of the program. The parallelization strategy used in the RHF, ROHF, UHF, and GVB sections of the program is described, and detailed speecup results are given. Parallel calculations can be run on ordinary workstations as well as dedicated parallel machines. © John Wiley & Sons, Inc.

17,580 citations

Journal ArticleDOI
TL;DR: The total energy deposited in the molecular ion is a control parameter which switches between three distinct fragmentation pathways: the sequential fragmentation in which the emission of an O(+) ion leaves a rotating CO(2+) ion behind that fragments after a time delay, the Coulomb explosion and an in-between fragmentation--the asynchronous dissociation.
Abstract: Fragmentation of highly charged molecular ions or clusters consisting of more than two atoms can proceed in a one step synchronous manner where all bonds break simultaneously or sequentially by emitting one ion after the other. We separated these decay channels for the fragmentation of CO(2)(3+) ions by measuring the momenta of the ionic fragments. We show that the total energy deposited in the molecular ion is a control parameter which switches between three distinct fragmentation pathways: the sequential fragmentation in which the emission of an O(+) ion leaves a rotating CO(2+) ion behind that fragments after a time delay, the Coulomb explosion and an in-between fragmentation--the asynchronous dissociation. These mechanisms are directly distinguishable in Dalitz plots and Newton diagrams of the fragment momenta. The CO(2)(3+) ions are produced by multiple electron capture in collisions with 3.2 keV/u Ar(8+) ions.

90 citations

Journal ArticleDOI
Abstract: In an experiment involving detection of a photoelectron and up to three photoions from CO{sub 2} in coincidence, we observe the triple ion coincidence C{sup +}:O{sup +}:O{sup +}. Moreover, we observe double coincidences between doubly charged cations and singly charged cation pairs C{sup 2+}:O{sup +}, O{sup 2+}:C{sup +}, O{sup 2+}:O{sup +}. These ion triplets and pairs arise from fragmentation of the triply charged molecular ion CO{sub 2}{sup 3+}. Other ion pairs--viz., C{sup +}:O{sup +}, O{sup +}:O{sup +}, O{sup +}:CO{sup +}--arising from the doubly charged molecular ion CO{sub 2}{sup 2+}, are also observed. From an analysis of the coincidence pattern we postulate four decay modes of the CO{sub 2}{sup 3+} ion. Kinetic energy release in the channel leading to C{sup +}:O{sup +}:O{sup +} is measured, and its distribution is postulated to have four contributing precursor states.

15 citations