Cold guided beams of water isotopologs

TL;DR

This study demonstrates the production of cold guided beams of water isotopologs using electrostatic velocity filtering, revealing how their different molecular properties affect guiding efficiency and matching experimental results with theoretical models.

Contribution

It provides a detailed comparison of experimental results with theoretical predictions for guiding different water isotopologs, highlighting the influence of molecular properties on Stark shifts.

Findings

Different isotopologs show distinct Stark shift behaviors.

Guided beam signals vary with electrode voltage and isotopolog.

Theoretical model accurately predicts experimental outcomes.

Abstract

Electrostatic velocity filtering and guiding is an established technique to produce high fluxes of cold polar molecules. In this paper we clarify different aspects of this technique by comparing experiments to detailed calculations. In the experiment, we produce cold guided beams of the three water isotopologs H2O, D2O and HDO. Their different rotational constants and orientations of electric dipole moments lead to remarkably different Stark shift properties, despite the molecules being very similar in a chemical sense. Therefore, the signals of the guided water isotopologs differ on an absolute scale and also exhibit characteristic electrode voltage dependencies. We find excellent agreement between the relative guided fractions and voltage dependencies of the investigated isotopologs and predictions made by our theoretical model of electrostatic velocity filtering.