Hamiltonian approach to the dissociation of a coupled nonlinear exciton-vibron system

D. Hennig, G. P. Tsironis, H. Gabriel

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We study the dissociation dynamics of polyatomic molecules using a Hamiltonian approach. Our model system consists of two molecular units, each having one electronic or vibrational state. An excitation is transferred between these two states with transfer matrix elements that depend on the intermolecular distance. The coupling with the intramolecular vibrations is included approximately through a cubic nonlinearity term while the intermolecular oscillations take place in a Morse potential. Dissociation in this model is a direct outcome of the coupling between the excitonic and vibrational subsystems leading to an energy exchange between the two. For small values of the transfer matrix elements we use the Melnikov function approach and show analytically the presence of homoclinic chaos in the system leading to dissociation for some bond configurations. The initial state preparation can drastically alter the dissociation process. We find that excitonic delocalization leads to enhanced dissociation rates. For larger intersite matrix elements we use the Chirikov overlap criterion to predict the onset of global phase space stochasticity, leading to dissociation for most bond lengths. The coupling to the intramolecular vibrations is seen to have an important effect on the dissociation phenomenon.

Original languageEnglish
Pages (from-to)3653-3664
Number of pages12
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume49
Issue number5
DOIs
Publication statusPublished - 1994
Externally publishedYes

Fingerprint

Exciton
excitons
dissociation
Transfer Matrix
Vibration
Melnikov Function
Morse Potential
vibration
Morse potential
Stochasticity
Homoclinic
polyatomic molecules
vibrational states
chaos
Overlap
Phase Space
Preparation
Chaos
Subsystem
Excitation

ASJC Scopus subject areas

  • Mathematical Physics
  • Physics and Astronomy(all)
  • Condensed Matter Physics
  • Statistical and Nonlinear Physics

Cite this

Hamiltonian approach to the dissociation of a coupled nonlinear exciton-vibron system. / Hennig, D.; Tsironis, G. P.; Gabriel, H.

In: Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, Vol. 49, No. 5, 1994, p. 3653-3664.

Research output: Contribution to journalArticle

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