# Pure Molecular Beam of Water Dimer

## TL;DR

This study demonstrates the spatial separation of water dimer molecules with high purity and low temperature using an electric deflector, and investigates their ionization behavior under strong laser fields, revealing proton transfer and dissociation pathways.

## Contribution

First to produce a pure, cold water dimer molecular beam via electric deflection and analyze its strong-field ionization dynamics.

## Key findings

- Water dimer beam with 93% purity and 1.5 K temperature achieved.
- Proton transfer observed in ionized water dimer.
- 46% of ionized dimers dissociate into H3O+ and neutral OH.

## Abstract

Spatial separation of water dimer from water monomer and larger water-clusters through the electric deflector is presented. A beam of water dimer with $93~\%$ purity and a rotational temperature of $1.5~$K was obtained. Following strong-field ionization using a $35~$fs laser pulse with a wavelength centered around $800~$nm and a peak intensity of $10^{14}~\text{W}/\text{cm}^2$ we observed proton transfer and $46~\%$ of the ionized water dimer broke apart into a hydronium ion $\text{H}_3\text{O}^+$ and neutral OH.