Structural Response of the Water Dimer to an Electric Field

Area of Science:

• Computational chemistry
• Physical chemistry
• Molecular dynamics

Background:

• Water dimer is a fundamental system for understanding hydrogen bonding.
• External electric fields can significantly influence molecular structures and properties.
• Density functional theory (DFT) is a powerful tool for simulating molecular behavior.

Purpose of the Study:

• To investigate the structural and electronic response of the water dimer to a uniform external electric field.
• To identify and characterize any field-induced structural transitions.
• To understand the mechanism and stability of the field-induced configurations.

Main Methods:

• Simulations using density functional theory (DFT).
• Gradual increase of external electric field intensity.
• Vibrational analysis to confirm stability of configurations.
• Hysteresis analysis to study system dynamics.

Main Results:

• A critical electric field strength was identified, inducing a structural transition.
• The water dimer reorients into a cis-like configuration with a unilateral hydrogen movement.
• The field-induced cis configuration represents a stable local minimum.
• Hysteresis was observed, stabilizing a high-dipole structure post-field removal.

Conclusions:

• External electric fields can induce significant structural changes in the water dimer.
• The transition involves a reorientation to a stable cis-like state.
• The system exhibits hysteresis, indicating distinct potential energy minima and memory effects.