Institute of Theoretical Physics

NA-QMD: Non-Adiabatic Quantum Molecular Dynamics

Theoretical Atomic and Molecular Physics Group

Introduction

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Publications

Dynamics in laser fields

 H2+:

C60: Giant breathing mode

Organic molecules: Isomerization

Dynamics in collisions

Ion - fullerene: "Stopping power"

Atom - cluster: Transparency

Cluster - cluster: Fusion

Kr8+ + N2: Coulomb explosion

Isomerization and Fragmentation of Ethylene C2H4

The dynamics of organic molecules in strong laser pulses depend sensitively on the frequency ω of the laser [1,2]. In the Fig. the absorption spectrum of C2H4 is shown. In the movies the (very different) relaxation dynamics of ethylene for different laser frequencies ω are shown.

Ethylene C2H4

ethylene

(a) Isomerization

At a laser frequency of ω=6.2 eV cis-trans isomerization occurs. The resulting state is vibrationally highly excited.

(b) "Fission"

At a laser frequency of 9.6 eV the C-C double bond is excited and the molecule immediatly undergoes "fission", i.e. C2H4 → 2 CH2.

(c) Multifragmentation

A a laser frequency of 19.3 eV all four C-H bonds are blasted away, i.e. C2H4 → C2 + 4H. The electronic density is shown in this movie.

Absorption spectrum of C2H4


(a)             (b)       (c)
Isomerization    "Fission" Multifragmentation



  1. T. Kunert, F. Grossmann, and R. Schmidt,
    Nonadiabatic dynamics of ethylene in femtosecond laser-pulses,
    Phys. Rev. A 72, 023422 (2005).

  2. J. Handt, T. Kunert, and R Schmidt,
    Fragmentation and cis-trans isomerization of diimide in fs laser-pulses,
    Chem. Phys. Lett. 428, 220 (2006).