Article (Scientific journals)
Adiabatic and diabatic invariants in ion-molecule reactions
Lorquet, Jean-Claude
2009In Journal of Chemical Physics, 131 (24)
Peer Reviewed verified by ORBi
 

Files


Full Text
diabatic invariants (2009).pdf
Publisher postprint (603.63 kB)
Download

All documents in ORBi are protected by a user license.

Send to



Details



Keywords :
Action integrals; Adiabatic invariants; ion-molecule reactions; reaction dynamics; Diabatic invariant; Effective potentials
Abstract :
[en] A point charge interacting with a dipole (either induced or permanent) constitutes a completely integrable dynamical subsystem characterized by three first integrals of the motion (E, pφ, and either 2 or a Hamilton-Jacobi separation constant Β). An ion-molecule reaction (capture or fragmentation) can be seen as an interaction between such a subsystem and a bath of oscillators. This interaction is a perturbation that destroys some of the first integrals. However, the perturbation depends on the separation between the fragments and the destruction is gradual. The mathematical simplicity of the long-range electrostatic interaction potential leads to useful simplifications. A first-order perturbation treatment based on the structured and regular nature of the multipole expansion is presented. The separating integrals valid in the asymptotic limit are found to subsist at intermediate distances, although in a weaker form. As the reaction coordinate decreases, i.e., as the fragments approach, the asymptotic range is followed by an outer region where (i) the azimuthal momentum pφ remains a constant of the motion; (ii) the square angular momentum 2 or the separation constant Β transform into a diabatic invariant in regions of phase space characterized by a high value of the translational momentum pr; (iii) for low values of pr, it is advantageous to use the action integral pθ dθ, which is an adiabatic invariant. The conditions under which an effective potential obtained by adding centrifugal repulsion to an electrostatic attractive term can be validly constructed are specified. In short, the dynamics of ion-molecule interactions is still regular in parts of phase space corresponding to a range of the reaction coordinate where the interaction potential deviates from its asymptotic shape. © 2009 American Institute of Physics.
Disciplines :
Chemistry
Author, co-author :
Lorquet, Jean-Claude ;  Université de Liège > Relations académiques et scientifiques (Sciences)
Language :
English
Title :
Adiabatic and diabatic invariants in ion-molecule reactions
Publication date :
2009
Journal title :
Journal of Chemical Physics
ISSN :
0021-9606
eISSN :
1089-7690
Publisher :
American Institute of Physics, United States - New York
Volume :
131
Issue :
24
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 08 September 2015

Statistics


Number of views
38 (0 by ULiège)
Number of downloads
168 (0 by ULiège)

Scopus citations®
 
0
Scopus citations®
without self-citations
0
OpenCitations
 
0

Bibliography


Similar publications



Contact ORBi