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Updated: May 24, 2026
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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Intense two-cycle laser pulses induce time-dependent bond hardening in a polyatomic molecule
1Tata Institute of Fundamental Research, Mumbai, India.
Physical Review Letters
|March 10, 2012
Summary
Researchers discovered time-dependent bond hardening in tetramethyl silane (TMS) molecules using intense, few-cycle laser pulses. This phenomenon prevents rapid dissociation, stabilizing the TMS molecular ion under specific conditions.
Area of Science:
- Physical Chemistry
- Molecular Dynamics
- Quantum Control
Background:
- Symmetrical molecules like tetramethyl silane (TMS) typically yield weak molecular ions in mass spectrometry due to rapid dissociation.
- Understanding molecular ion stability under intense laser fields is crucial for advanced spectroscopy and chemical analysis.
Purpose of the Study:
- To investigate the influence of intense, few-cycle laser pulses on the stability of polyatomic molecular ions.
- To explore the phenomenon of time-dependent bond hardening in tetramethyl silane.
Main Methods:
- Utilizing intense, few-cycle (800 nm) laser pulses to probe tetramethyl silane.
- Employing time-resolved measurements to observe molecular ion dynamics and dissociation pathways.
- Comparing results obtained with few-cycle pulses versus longer-duration (≥100 fs) pulses.
Main Results:
- A novel time-dependent bond-hardening process was observed in tetramethyl silane.
- Few-cycle intense laser pulses create a field-induced potential well, trapping wave packets and stabilizing the TMS molecular ion.
- Longer laser pulses (≥100 fs) showed a decrease in bond hardening, allowing the wave packet to escape and destabilizing the TMS molecular ion.
Conclusions:
- Time-dependent bond hardening is a viable mechanism to control molecular ion stability.
- The duration of intense laser pulses critically influences the observed bond-hardening effect.
- This discovery opens new avenues for manipulating molecular dissociation dynamics using tailored laser fields.
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