Isotope-Selective Strong Field Ionization of Semi-Heavy Water

TL;DR

This study demonstrates that tailored ultrafast laser pulses can selectively ionize specific bonds in semi-heavy water molecules, revealing bond-specific ionization dynamics through 3D momentum measurements.

Contribution

It introduces a method for isotope-selective strong field ionization of HOD using a pair of femtosecond laser pulses, enabling bond-specific control and measurement.

Findings

Selective ionization along the OH bond was achieved.

Bond stretching and unbending occur before selective ionization.

3D momentum measurements confirmed bond-specific ionization dynamics.

Abstract

Semi-heavy water (HOD) is one of the simplest molecules in which the bonds are labelled by isotope. We demonstrate that a pair of intense few-femtosecond infrared laser pulses can be used to selectively tunnel ionize along one of the two bonds. The first pulse doubly ionizes HOD, inducing rapid bond stretching and unbending. Femtoseconds later, the second pulse arrives and further ionization is selectively enhanced along the OH bond. These conclusions arise from 3D time-resolved measurements of H$^+$, D$^+$, and O$^+$ momenta following triple ionization.