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Probing Isomerization Dynamics via a Dipole-Bound State
Yuzhu Lu1, Rulin Tang1, Rui Zhang1
1Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.
The Journal of Physical Chemistry Letters
|September 12, 2022
Summary
We observed molecular isomerization dynamics in sodium chloride dimer using a dipole-bound state. The electron in the dipole-bound state probes the salt dimer
Area of Science:
- Physical Chemistry
- Quantum Dynamics
- Spectroscopy
Background:
- Observing molecular isomerization dynamics is a key challenge in physical chemistry.
- Dipole-bound states (DBS) offer a pathway to probe isomerization of neutral molecules.
- The electron in a DBS can act as a messenger for these dynamic processes.
Purpose of the Study:
- To investigate the isomerization dynamics of the sodium chloride (NaCl)₂ dimer from a linear to a rhombic configuration.
- To utilize a dipole-bound state (DBS) as a probe for this isomerization process.
- To analyze the electron autodetachment dynamics and energy distributions.
Main Methods:
- Cryogenic photoelectron spectroscopy was employed to study the (NaCl)₂ dimer.
- Ab initio calculations were performed to support the experimental observations.
- The dynamics of the dipole-bound state (DBS) of the (NaCl)₂ anion were analyzed.
Main Results:
- The (NaCl)₂ anion in its DBS can undergo autodetachment due to linear-to-rhombic isomerization, even when the DBS energy is below the neutral electron affinity.
- The ground DBS exhibits a relatively long lifetime (nanoseconds) attributed to quantum tunneling during isomerization.
- Vibrationally excited DBS have significantly shorter lifetimes (picoseconds), and electron autodetachment shows thermionic emission characteristics.
Conclusions:
- Dipole-bound states are effective messengers for observing molecular isomerization dynamics.
- Quantum tunneling plays a crucial role in the isomerization dynamics of the (NaCl)₂ anion's DBS.
- The observed thermionic emission-like electron energy distribution provides novel insights into autodetachment processes.
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