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Published on: August 17, 2017
Phase sensitive control of vibronic guest-host interaction: Br2 in Ar matrix
Heide Ibrahim1, Mónika Héjjas, Mizuho Fushitani
1Institut fr Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
The Journal of Physical Chemistry. A
|March 25, 2009
Summary
Femtosecond laser pulse shaping precisely controls vibronic progressions for coherent chromophore excitation. This method reliably generates phase-controlled pulse trains, enabling detailed study of molecular dynamics and coherence.
Area of Science:
- Ultrafast spectroscopy
- Quantum optics
- Molecular dynamics
Background:
- Vibronic progressions govern light-matter interactions in molecules.
- Controlling molecular excitation with ultrashort pulses is crucial for understanding dynamics.
- Femtosecond pulse shaping offers precise control over excitation pathways.
Purpose of the Study:
- To program vibronic progressions into a pulse shaper for controlled chromophore excitation.
- To generate and characterize femtosecond pulse trains for studying molecular coherence.
- To investigate the role of zero phonon lines and phonon sidebands in coherent dynamics.
Main Methods:
- Utilizing a pulse shaper to convert programmed vibronic progressions into femtosecond pulse trains via Fourier transformation.
- Employing a Michelson interferometer for phase-sensitive wave packet superposition and coherence time determination.
- Achieving spectral resolution of 1 nm within a 20 nm envelope, generating seven phase-controlled 40 fs subpulses separated by 250 fs.
Main Results:
- Demonstrated reliable generation of phase-controlled femtosecond pulse trains.
- Observed agreement between double pulse results and phase-sensitive wave packet superposition.
- Reproducing B state vibronic progressions (ZPL and PSB) in the chromophore for coherent accumulation.
- B state ZPL wave packet dynamics dominated pump-probe spectra due to coherence.
Conclusions:
- Femtosecond pulse shaping is effective for programming and controlling vibronic progressions.
- Phase-sensitive techniques reliably characterize coherence in molecular systems.
- Coherent subpulse accumulation via ZPL and PSB demonstrates control over molecular dynamics.
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