Reference : Unimolecular Dynamics from Kinetic Energy Release Distributions. V. How does the Effi...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/742
Unimolecular Dynamics from Kinetic Energy Release Distributions. V. How does the Efficiency of Phase Space Sampling vary with Internal Energy?
English
[fr] La dynamique unimoléculaire telle que déduite des distributions d'énergie cinétique. Comment varie l'efficacité d'échantillonnage de l'espace des phases avec l'énergie interne.
Hoxha, A. [ > > ]
Locht, Robert mailto [Université de Liège - ULg > Département de Chimie (Faculté des sciences) > Laboratoire de Dynamique Moléculaire (Sciences) > >]
Lorquet, Andrée mailto [Université de Liège - ULg > Département de chimie (sciences) > Laboratoire de dynamique moléculaire >]
Lorquet, Jean-Claude mailto [Université de Liège - ULg > Département de Chimie (Faculté des sciences) > Laboratoire de Dynamique Moléculaire (Sciences) > >]
Leyh, Bernard mailto [Université de Liège - ULg > Département de chimie (sciences) > Laboratoire de dynamique moléculaire >]
1999
Journal of Chemical Physics
American Institute of Physics
111
20
9259-9266
Yes (verified by ORBi)
International
0021-9606
1089-7690
New York
USA
[en] Retarding Field analysis ; KERD ; Dissociative photoionization ; Maximum Entropy Method (MEM) ; He(I), Ne(I), Ar(II) ; Ab initio Calculations
[fr] C2H3+/C2H3Br
[en] A retarding field technique coupled with a quadrupole mass analyzer has been used to obtain the kinetic energy release distributions (KERDs) for C2H3Br+->[C2H3]++Br dissociation as a function of the internal energy. The KERDs obtained by dissociative photoionization using the He(I), Ne(I) and Ar(II) resonance lines were analyzed by the maximum entropy method and were found to be well described by introducing a single dynamical constraint, namely the relative translational momentum of the fragments. Ab initio calculations reveal the highly fluxional character of the C2H3+ ion. As the energy increases, several vibrational modes are converted in turn into large-amplitude motions. Our main result is that, upon increasing internal energy, the fraction of phase space sampled by the pair of dissociating fragments is shown to first decrease, pass through a shallow minimum around 75%, and then increase again, reaching almost 100% at high internal energies (8 eV). This behaviour at high internal energies is interpreted as resulting from the conjugated effect of intramolecular vibrational redistribution (IVR) and radiationless transitions among potential energy surfaces. Our findings are consistent with the coincidence data of Miller and Bear, reanalyzed here, and with the KERD of the metastable dissociation.
Laboratoire de Dynamique Moléculaire
ARC Contract
Researchers
http://hdl.handle.net/2268/742
http://jcp.aip.org/jcp.copyright.jsp
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