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Fragment momentum distributions obtained from coupled electron-nuclear dynamics
1Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Würzburg, Germany.
The Journal of Chemical Physics
|March 20, 2012
Summary
Femtosecond laser pulses induce molecular fragmentation. Electron and nuclear motion dictate fragmentation patterns, with time-delayed pulses creating unique nuclear momentum structures influenced by electronic states.
Area of Science:
- Quantum dynamics
- Molecular fragmentation
- Ultrafast spectroscopy
Background:
- Understanding molecular fragmentation dynamics is crucial for controlling chemical reactions.
- Femtosecond laser pulses provide a tool to probe ultrafast electronic and nuclear motion.
- Theoretical models are essential for interpreting complex experimental observations.
Purpose of the Study:
- To theoretically investigate molecular fragmentation induced by femtosecond laser pulses.
- To analyze the influence of coupled electronic and nuclear motion on fragmentation patterns.
- To explore interference effects arising from multiple pulse excitations and electronic wave-packet dynamics.
Main Methods:
- Development of a theoretical model incorporating both electronic and nuclear motion.
- Simulation of molecular response to single and time-delayed femtosecond laser pulses.
- Analysis of electron and nuclear momentum distributions.
Main Results:
- Single-pulse excitation yields diffraction patterns in electron momentum, sensitive to electronic states and nuclear charge distribution.
- Two time-delayed pulses generate additional structures in nuclear momentum distributions within the same dissociation channel.
- Electronic degrees of freedom significantly modify these momentum distributions.
- Simultaneous excitation of different electronic states leads to interferences linked to attosecond electronic wave-packet dynamics.
Conclusions:
- Femtosecond laser-induced fragmentation is highly sensitive to the interplay of electronic and nuclear motion.
- Time-delayed and simultaneous multi-pulse excitations offer pathways to control and probe molecular dynamics with attosecond precision.
- The theoretical model provides insights into complex fragmentation mechanisms and interference phenomena.
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