Electron-Binding Dynamics of the Dipole-Bound State: Correlation Effect on the Autodetachment Dynamics

Area of Science:

• Physical Chemistry
• Quantum Chemistry
• Chemical Physics

Background:

• Dipole-bound states (DBS) are anions where an excess electron is weakly bound to a neutral molecule with a significant dipole moment.
• The charge-dipole electrostatic potential is conventionally considered the primary force responsible for electron binding in DBS.
• The role of nonclassical electron correlation in DBS stability and dynamics remains an area of active investigation.

Purpose of the Study:

• To investigate the electron-binding forces in dipole-bound states (DBS) of bromophenoxide anions.
• To examine the autodetachment dynamics from DBS Feshbach resonances and their dependence on bromine substitution.
• To elucidate the contributions of electron correlation to the binding energies and autodetachment rates in these exotic anion species.

Main Methods:

• Picosecond time-resolved photoelectron velocity-map imaging spectroscopy to observe real-time autodetachment dynamics.
• High-level ab initio quantum chemical calculations using EOM-EA-CCSD to determine binding energies.
• Semiclassical quantum dynamics simulations informed by ab initio calculations to model autodetachment rates.

Main Results:

• Autodetachment dynamics from DBS Feshbach resonances of bromophenoxide anions cannot be explained by the conventional charge-dipole potential alone.
• Autodetachment lifetimes are significantly altered by the position of bromine substitution, a trend not predicted by charge-dipole models.
• EOM-EA-CCSD calculations provide more accurate binding energies than DFT, and dynamics simulations based on these calculations successfully predict autodetachment rate trends.

Conclusions:

• Electron correlation plays a crucial role in the static and dynamic properties of the excess electron in DBS.
• Interactions between the dipole-bound electron and the polarizable bromine atom's orbitals significantly influence electron binding and autodetachment.
• These findings highlight the importance of electron correlation in understanding the behavior of exotic anion species.