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See detailThe Dissociative Ionization of C2H2. The C+, C2+ and CH2+ Dissociation Channels. The Vinylidene Ion as a Transient?
Locht, Robert ULg; Davister, M.

in Chemical Physics (1995), 195

The dissociative electroionization of C2H2 has been investigated in the C+, C2+ and CH2+ dissociation channels. Both the translational energy and the appearance energies have been measured. The kinetic ... [more ▼]

The dissociative electroionization of C2H2 has been investigated in the C+, C2+ and CH2+ dissociation channels. Both the translational energy and the appearance energies have been measured. The kinetic energy versus appearance energy diagrams related to these species are discussed in detail and dissociation mechanisms are proposed for all observed onset energies. For the three ionic species, the dissociation pathways leading to the fragmentation of C2H2+ into C+, C2+ and CH2+ successively have to run very likely over an isomerization mechanism of the molecular ion. The isomeric vinylidene structure could be the most probable intermediate. [less ▲]

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See detailThe Dissociative Ionization of C2H2. The H-C2H Binding Energy.
Davister, M.; Locht, Robert ULg

in Cornides, I.; Horvath, G.; Veakey, K. (Eds.) Book of Abstracts. Advances in mass spectrometry Volume 13 (13th IMSC Budapest 94) (1994)

The dissociative electroionization measurements on C2H+/C2H2 are reported. Kinetic energy and appearance energies are measured. On these data the D(H-C2H) binding energy is deduced.

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See detailThe Dissociative Ionization of Carbon Dioxide below 21.22 eV. A high Resolution PIPECO spectroscopic investigation.
Locht, Robert ULg

in International Journal of Mass Spectrometry and Ion Processes (1995), 148

The photoion-photoelectron spectrum of O+, CO+ and CO2+ has been investigated under high resolution conditions. The O+ ion production is found not to be restricted to the CO2+ (C2Sigma+/g,0,0,0 ... [more ▼]

The photoion-photoelectron spectrum of O+, CO+ and CO2+ has been investigated under high resolution conditions. The O+ ion production is found not to be restricted to the CO2+ (C2Sigma+/g,0,0,0) predissociation. The (0,1,0) and (1,0,0) levels are clearly shown to be involved. The CO+ ion production involves all the vibrational states reached in the Franck-Condon region, i.e. up to (2,0,1) at 19.94 eV. The CO2+ molecular ion does not survive the predissociation in the entire range covered in the present work. [less ▲]

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See detailDissociative Ionization of Carbon Disulphide in the Gas Phase. Heat of Formation of the CS Radical.
Hubin-Franskin, Marie-Jeanne ULg; Locht, Robert ULg; Katihabwa, J.

in Chemical Physics Letters (1976), 37(3), 488-493

Measurements of the appearance potentials and the kinetic energies of S+ and CS+ ions formed by electron impact on carbon disulphide in the gas phase lead us to propose a value as low as 34+/-6 kcal/mole ... [more ▼]

Measurements of the appearance potentials and the kinetic energies of S+ and CS+ ions formed by electron impact on carbon disulphide in the gas phase lead us to propose a value as low as 34+/-6 kcal/mole for the heat of formation of the CS radical in its ground electronic state. It is also shown that the predissociation of the A2Piu or X2Pig and the B2Sigmau/+ molecular ion states by a repulsive 4Sigma- state giving rise to S+ ions, observed through metastastable ions study, occur at 13.45 eV and 14.55 eV respectively. [less ▲]

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See detailThe Dissociative Ionization of Carbon Monoxide.
Locht, Robert ULg

in Chemical Physics (1977), 22

The dissociative ionization of CO by low energy electron impact into C+ and O (or O-) and O+ and C (or C-) is investigated using ion energy and mass analysis. The kinetic energy distributions are studied ... [more ▼]

The dissociative ionization of CO by low energy electron impact into C+ and O (or O-) and O+ and C (or C-) is investigated using ion energy and mass analysis. The kinetic energy distributions are studied as a function of the impinging electron energy. The threshold energies of C+ and O+ are measured as a function of the released kinetic energy. The formation of the products in their ground level and with a small amount of kinetic energy mainly occurs through predissociation. The CO+ electronic states involved in these processes are tentatively identified. New evidences have been found for the importance of dissociative ionization via autoionization. [less ▲]

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See detailThe Dissociative Ionization of CH3F. A Mass Spectrometric Photoionization study using Synchrotron Radiation.
Locht, Robert ULg; Rühl, E.; Momigny, J. et al

in Gilbody, H. B.; Newell, W. R.; Read, F. H. (Eds.) et al Electronic and Atomic Collisions: Abstracts of Contributed Papers. (1987)

The dissociation channel of CH3F+hnu->CH3++F has been investigated by photoionization using synchrotron radiation. The kinetic energy-versus-appearance energy diagram of CH3+ has been reported and ... [more ▼]

The dissociation channel of CH3F+hnu->CH3++F has been investigated by photoionization using synchrotron radiation. The kinetic energy-versus-appearance energy diagram of CH3+ has been reported and analyzed. [less ▲]

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See detailDissociative Ionization of CH4 and CD4 by low energy Electron impact. The Proton Formation.
Olivier, J. L.; Locht, Robert ULg; Momigny, J.

in Electronic and Atomic Collisions: Abstract of contributed papers. Volume 1. (1979)

The kinetic energy distributions of H+(D+)/CH(D)4 are produced at variable electron impact energies. Two different features are observed and are interpreted in terms of dissociative autoionization.

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See detailThe dissociative Ionization of CO by Electron Impact: the C+ ion formation.
Locht, Robert ULg; Dürer, J. M.

in Risley, J. S.; Geballe, R. (Eds.) Electronic and Atomic Collisions. Abstracts of papers of the IXth International Conference on the Physics of Electronic and Atomic Collisions. (1975)

The dissociative ionization of CO by low-energy electron impact is presented. The results on the dissociation channel of C+ formation has been investigated and is discussed.

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See detailThe Dissociative Ionization of Methyl Fluoride. The formation of CH2+ and CH3+.
Locht, Robert ULg; Momigny, J.

in International Journal of Mass Spectrometry and Ion Physics (1986), 71

The decay of ionized CH3F was investigated in the CH2+ and CH3+ dissiciation channels by electronionization and fixed wavelength photoionization using HeI and NeI resonance lines. The translational energy ... [more ▼]

The decay of ionized CH3F was investigated in the CH2+ and CH3+ dissiciation channels by electronionization and fixed wavelength photoionization using HeI and NeI resonance lines. The translational energy spectra, ionization efficiency curves and kinetic energy-versus-appearance enegy diagrams of both ions were measured. Although dissociative autoionization is the prominent dissociation mechanism for the appearance of CH2+ and CH3+, direct dissociative ionization is observed for CH2+ at 23.4 eV and for CH3+ at 16.5 eV. [less ▲]

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See detailDissociative Ionization of N2 by Electron Impact.
Locht, Robert ULg; Schopman, Joop

in Cobic, B. C.; Kurepa, M. V. (Eds.) Electronic and Atomic Collisions. Abstracts of Papers: VIII ICPEAC, Beograd, 1973. Volume 1. (1973)

The dissociative ionization by electron impact of N2 is presented: the kinetic energy distribution of N+ and the major features characterized by their energy.

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See detailThe Dissociative Ionization of N2O by low energy Electron Impact: the N+ and N2+ Dissociation Channels.
Locht, Robert ULg; Olivier, J. L.; Beeckman, W. et al

in XII International Conference on the Physics of Electronic and Atomic Collisions: Abstracts of Contributed Papers. (1981)

The kinetic energy-versus-appearance energy diagram obtained for N+ and N2+ from N2O by electron impact is discussed.

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See detailThe Dissociative Ionization of Nitrogen.
Locht, Robert ULg; Schopman, Joop; Wankenne, H. et al

in Chemical Physics (1975), 7

Energy distributions and appearance potentials of N+ ions produced by low-energy electron impact on N2 have been measured. At least five dissociaton limits were detected either directly or by ... [more ▼]

Energy distributions and appearance potentials of N+ ions produced by low-energy electron impact on N2 have been measured. At least five dissociaton limits were detected either directly or by extrapolation of the 1/2 slope straight lines drawn through the kinetic energy versus appearance potential energy diagram. Fine structure observed at low energy has been interpreted by the predissociation of at least two N2+ excited states one of which being the well-known C2Sigmau/+ state. One of the others could be a 2Piu state predissociated to the dissociation limit at 24.34 eV. Close correlation between the results of the present work and the photoelectron spectroscopic observations could be done over the electron energy range between 24.3 eV and 36 eV and assignments are discussed in detail. [less ▲]

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See detailThe Dissociative Ionization of Nitrous Oxide. A comparison between Electroionization and HeI and NeI Photoionization.
Locht, Robert ULg; Caprace, G.; Momigny, J.

in Chemical Physics Letters (1984), 111

The photoelectron spectrum of N2O and the kinetic energy distributions of NO+, N2+, O+ and N+ have been recorded with HeI and NeI resonance lines. At 21.22 eV the distributions are similar to those ... [more ▼]

The photoelectron spectrum of N2O and the kinetic energy distributions of NO+, N2+, O+ and N+ have been recorded with HeI and NeI resonance lines. At 21.22 eV the distributions are similar to those observed by electroionization at comparable energy. The NeI resonance line produces O+ and NO+ ions. Their respective kinetic energy distributions are related to the change induced in the N2O+(A2Sigma+) photoelectron band excited by the NeI resonance line. [less ▲]

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See detailThe Dissociative ionization of Nitrous Oxide. An Electroionization Study.
Olivier, J. L.; Locht, Robert ULg; Momigny, J.

in International Journal of Mass Spectrometry and Ion Physics (1984), 58

The dissociative electroionization of nitrous oxide into its four dissociation channels has been studied by a method using the kinetic energy and mass analysis. The formation of N2+, NO+, O+ and N+ are ... [more ▼]

The dissociative electroionization of nitrous oxide into its four dissociation channels has been studied by a method using the kinetic energy and mass analysis. The formation of N2+, NO+, O+ and N+ are discussed essentially in terms of predissociation of the ground and excited N2O+ states between 15 and 40 eV. In most cases the predissociating states are also identified. The present results are compared with those in the literature. [less ▲]

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See detailDissociative Ionization of O2 by Electron Impact.
Locht, Robert ULg; Schopman, Joop

in Cobic, B. C.; Kurepa, M. V. (Eds.) Electronic and Atomic Collisions. Abstract of Papers. VIII ICPEAC, Beograd, 1973. Volume 1. (1973)

The dissociative ionization by electron impact of O2 is presented: the kinetic energy distribution of O+ and the major structures characterized by their energy.

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See detailThe Dissociative Photoionization of Ammonia. The Formation of NH2+, NH+ and N+.
Locht, Robert ULg; Hagenow, G.; Denzer, W. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H. (BESSY) (1988)

The dissociative ionization of NH3 has been investigated by photoionization using synchrotron radiation. Appearance energies and the kinetic energy of NH2+, NH+ and N+ are reported.

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See detailThe Dissociative Photoionization of CH3F.
Locht, Robert ULg; Rühl, E.; Momigny, J. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H. (BESSY) (1987)

The kinetic energy distributions of CH3+/CH3F are measured at different wavelengths using monochromatized synchrotron radiation. The ionization efficiency curves of CH3+ are measured for different kinetic ... [more ▼]

The kinetic energy distributions of CH3+/CH3F are measured at different wavelengths using monochromatized synchrotron radiation. The ionization efficiency curves of CH3+ are measured for different kinetic energies. The resulting kinetic energy-versus-appearance energy is reported. [less ▲]

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See detailThe Dissociative Photoionization of O2 and N2O.
Locht, Robert ULg; Hagenow, G.; Rühl, E. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H. (BESSY) - Jahresbericht/Annual Report (1987)

The dissociative photoionization of O2 and N2O is investigated using synchrotron radiation. The results on the O+ and NO+ dissociation channels are reported.

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See detailLa dissolution pour justes motifs: quel avenir?
Caprasse, Olivier ULg; Aydogdu, Roman ULg

in Revue Pratique des Sociétés Civiles et Commerciales (2005)

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See detailDissolved inorganic carbon dynamics and air-sea carbon dioxide fluxes during coccolithophore blooms in the northwest European continental margin (northern Bay of Biscay)
Suykens, Kim; Delille, Bruno ULg; Chou, Lei et al

in Global Biogeochemical Cycles (2010), 24

We report a data set of dissolved inorganic carbon (DIC) obtained during three cruises in the northern Bay of Biscay carried out in June 2006, May 2007, and May 2008. During these cruises, blooms of the ... [more ▼]

We report a data set of dissolved inorganic carbon (DIC) obtained during three cruises in the northern Bay of Biscay carried out in June 2006, May 2007, and May 2008. During these cruises, blooms of the coccolithophore Emiliania huxleyi occurred, as indicated by patches of high reflectance on remote sensing images, phytoplankton pigment signatures, and microscopic examinations. Total alkalinity showed a nonconservative behavior as a function of salinity due to the cumulative effect of net community calcification (NCC) on seawater carbonate chemistry during bloom development. The cumulative effect of NCC and net community production (NCP) on DIC and the partial pressure of CO2 (pCO(2)) were evaluated. The decrease of DIC (and increase of pCO(2)) due to NCC was overwhelmingly lower than the decrease of DIC (and decrease of pCO(2)) due to NCP (NCC: NCP << 1). During the cruises, the northern Bay of Biscay acted as a sink of atmospheric CO2 (on average similar to-9.7 mmol C m(-2) d(-1) for the three cruises). The overall effect of NCC in decreasing the CO2 sink during the cruises was low (on average similar to 12% of total air-sea CO2 flux). If this is a general feature in naturally occurring phytoplankton blooms in the North Atlantic Ocean (where blooms of coccolithophores are the most intense and recurrent), and in the global ocean, then the potential feedback on increasing atmospheric CO2 of the projected decrease of pelagic calcification due to thermodynamic CO2 "production" from calcification is probably minor compared to potential feedbacks related to changes of NCP. [less ▲]

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