References of "Leyh, Bernard"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailElectronic Autoionization in Carbon monoxide: The effects of the Vibrational Motion.
Leyh, Bernard ULg; Delwiche, Jacques ULg; Hubin-Franskin, Marie-Jeanne ULg et al

in Chemical Physics (1987), 115

New continuous measurements of the vibrationally resolved photoionization cross sections of CO+ X2Sigma+ and A2Pi between 63 and 83 nm are reported. We assign the Rydberg series converging to CO+ A2Pi ... [more ▼]

New continuous measurements of the vibrationally resolved photoionization cross sections of CO+ X2Sigma+ and A2Pi between 63 and 83 nm are reported. We assign the Rydberg series converging to CO+ A2Pi. The effects of the vibrational motion are interpreted on the basis of the Condon approximation. This approximation is shown to allow a qualitative understanding of the decay of the Rydberg series converging to the A2Pi and B2Sigma+ states of CO+. [less ▲]

Detailed reference viewed: 16 (1 ULg)
Full Text
Peer Reviewed
See detailTheoretical Study of Electronic Autoionization in CO: Vibrationally resolved results between 17 and 18.3 eV.
Leyh, Bernard ULg; Raseev, G.

in Physical Review. A : General Physics (1986), 34(4), 2920-2935

We have theoretically studied the electronic autoionization between 17 and 18.3 eV of Rydberg series converging to the B 2Sigma+ state of CO+ (RB series). We have obtained partial and vibrationally ... [more ▼]

We have theoretically studied the electronic autoionization between 17 and 18.3 eV of Rydberg series converging to the B 2Sigma+ state of CO+ (RB series). We have obtained partial and vibrationally resolved differential and total photoionization cross sections by combining ab initio electronic quantities with a variant of the two-step multichannel quantum defect theory (MQDT). The formalism of the Feshbach projection operators is used to separate the electronic quantities needed in the first and second steps of the MQDT. We have introduced the vibrational motion within the Condon approximation. Our results lead to new unambiguous assignments of the RB series. The vibrationally resolved cross sections, the associated branching ratios, and the background and resonant features are discussed in detail and compared with the available experimental data. There is an overall agreement between theory and experiement except for the angular distribution of photoelectrons. [less ▲]

Detailed reference viewed: 11 (3 ULg)
Full Text
Peer Reviewed
See detailAutoionization in Diatomic Molecules: an example of Electrostatic Autoionization in CO.
Raseev, G.; Leyh, Bernard ULg; Lefebvre-Brion, H.

in Zeitschrift für Physik. D, Atoms, Molecules, and Clusters (1986), 2

A review is presented of the different types of autoionization which have been studied theoretically in diatomic molecules: electronic (or electrostatic), rotational, spin-orbit and vibrational ... [more ▼]

A review is presented of the different types of autoionization which have been studied theoretically in diatomic molecules: electronic (or electrostatic), rotational, spin-orbit and vibrational autoionizations. An example involving a large number of vibrational channels is treated. It concerns the electrostatic autoionization in the 730-708 Angstöm wavelength region which appears in the CO photoionization spectrum. The structure observed at 721 Angstrôm is explained by the enhancement in intensity of numerous levels of Rydberg series converging to excited levels of the A 2Pi state caused by two autoionized Rydberg levels with a B 2Sigma+ core. [less ▲]

Detailed reference viewed: 29 (1 ULg)
Full Text
See detailMeasured and Calculated Partial Photoionization Cross Sections of CO between 15 and 40 eV.
Leyh, Bernard ULg; Raseev, G.; Hubin-Franskin, Marie-Jeanne ULg et al

in Lahmani, F.; Castex, M. C.; Collin, Jacques (Eds.) et al Photophysics and Photochemistry above 6 eV. (1985)

Vibrationally resolved partial photoionization cross sections of CO have been measured and theoretical partial cross sections have been calculated using the method of Raseev et al. and the two-step MQDT ... [more ▼]

Vibrationally resolved partial photoionization cross sections of CO have been measured and theoretical partial cross sections have been calculated using the method of Raseev et al. and the two-step MQDT formulation of Giusti-Suzor and Lefebvre-Brion. We discuss the physical nature of the shape resonances appearing in the epsilon-sigma continua and we analyze their vibrational selectivity. A new assignment of the Rydberg series converging to CO+(B2Sigma+) is suggested and their electronic and vibrational selectivity is discussed. [less ▲]

Detailed reference viewed: 31 (1 ULg)
Full Text
See detailPotential Energy Surfaces and Theory of Unimolecular Dissociation.
Lorquet, Jean-Claude ULg; Leyh, Bernard ULg

in Almoster Ferreira, M. A. (Ed.) Ionic Processes in the Gas Phase. (1984)

Reaction mechanisms can be determined from ab initio calculations of potential energy surfaces. Their complicated nature explains the frequent success of statistical theories, but non-statistical ... [more ▼]

Reaction mechanisms can be determined from ab initio calculations of potential energy surfaces. Their complicated nature explains the frequent success of statistical theories, but non-statistical behaviour is also accounted for. A certain correlation between structure and reactivity can be established, subject to many qualifications. Information on the nuclear motion on the potential energy surfaces of an ionized molecule can be extracted from a photoelectron spectrum by a Fourier transform operation. [less ▲]

Detailed reference viewed: 19 (0 ULg)
Full Text
Peer Reviewed
See detailIntramolecular Dynamics of Molecular Ions.
Lorquet, Jean-Claude ULg; Lorquet, Andrée ULg; Dehareng, Dominique ULg et al

in Bulletin de la Société Chimique Belge (1983), 92(6/7), 609-611

The Fourier transform of an electronic spectrum gives a direct dynamic information on the nuclear motion of a wavepacket on the potential energy surface of the final state reached in the electronic ... [more ▼]

The Fourier transform of an electronic spectrum gives a direct dynamic information on the nuclear motion of a wavepacket on the potential energy surface of the final state reached in the electronic transition, at least during the first few molecular vibrations. The method is valid for both adiabatic and non-adiabatic situations. It has proved its usefulness in the study of molecular processes such as Duchinsky effect, fast predissociations and internal conversions. [less ▲]

Detailed reference viewed: 43 (13 ULg)
Full Text
Peer Reviewed
See detailLineweaver-Burk, Hanes, Eadie-Hofstee and Dixon Plots in Non-steady-state Situations.
Frère, Jean-Marie ULg; Leyh, Bernard ULg; Renard, André

in Journal of Theoretical Biology (1983), 101

Lineweaver-Burk, Hanes, Eadie-Hofstee and Dixon plots can only be used when a true initial rate is measured. Despite the fact that this point has often been stressed, it is far too often ignored in favour ... [more ▼]

Lineweaver-Burk, Hanes, Eadie-Hofstee and Dixon plots can only be used when a true initial rate is measured. Despite the fact that this point has often been stressed, it is far too often ignored in favour of restricting the essay time to one where low amounts of substrate are used. When one or several irreversible and slow steps occur with an inactivator during the incubation of a ternary enzyme-substrate-inactivator mixture, the rate of the enzyme-catalyzed reaction progressively decreases. Even under these conditions, the present computer simulations investigations show that apparently linear Lineweaver-Burk, Hanes, Eadie-Hofstee and Dixon graphs can be obtained when the amount of product is mistakenly assumed to represent the true initial rate. Moreover, the observed pattern can change with time, going for instance from non-competitive to competitive. "Ki's" measured under these conditions also vary with time and bear little relationship to the true constants involved in the interaction. [less ▲]

Detailed reference viewed: 276 (1 ULg)
Full Text
Peer Reviewed
See detailIntramolecular dynamics by photoelectron spectroscopy. II. Nonadiabatic processes.
Dehareng, Dominique ULg; Leyh, Bernard ULg; Desouter-Lecomte, Michèle ULg et al

in Journal of Chemical Physics (1983), 79(8), 3719-3724

The Fourier transform of an electronic spectrum leads to an autocorrelation function which provides information on the propagation of the wave packet on the potential energy surface of the electronic ... [more ▼]

The Fourier transform of an electronic spectrum leads to an autocorrelation function which provides information on the propagation of the wave packet on the potential energy surface of the electronic state reached in the transition. The formula is valid even when nonadiabatic interaction is present, i.e., when the wave packet splits at a particular surface crossing with one part branching off to another potential energy surface. An explicit expression of the correlation function is given for a model of several discrete states interacting with a continuum. Closed-form solutions are given in the case of one and two resonances. A very simple formula valid in the strong coupling limit is also derived. The method is applied to the photoelectron spectrum of state A 2Sigma+ of HBr+, which is shown to correspond to the strong couplig case. [less ▲]

Detailed reference viewed: 21 (5 ULg)