# Sub-femtosecond tracing of molecular dynamics during strong-field interaction

## TL;DR

This paper presents a novel experimental method for simultaneously measuring nuclear and electronic dynamics in molecules during strong-field interactions with sub-femtosecond resolution, providing new insights into early molecular processes.

## Contribution

The authors introduce an experimental technique that captures both nuclear and electronic motions in molecules during strong-field ionization with unprecedented temporal and spatial resolution.

## Key findings

- Direct observation of nuclear wavepacket evolution on H2+
- Simultaneous measurement of electronic and nuclear dynamics
- Attosecond temporal and picometer spatial resolution achieved

## Abstract

We introduce and experimentally demonstrate a method, where the two intrinsic time scales of a molecule, the slow nuclear motion and the fast electronic motion, are simultaneously measured in a photo-electron photo-ion coincidence experiment. In our experiment, elliptically polarized, 750~nm, 4.5~fs laser pulses were focused to an intensity of $9\times10^{14}\mathrm{W/cm}^2$ onto H$_2$. Using coincidence imaging, we directly observe the nuclear wavepacket evolving on the \ssg{} state of H$_2^+$ during its first roundtrip with attosecond temporal and picometer spatial resolution. The demonstrated method should enable insight into the first few femtoseconds of the vibronic dynamics of ionization-induced unimolecular reactions of larger molecules.