How the hydrogen bond in NH$_4$F is revealed with Compton scattering

TL;DR

This study uses Compton scattering experiments and ab initio calculations to reveal the hydrogen bonding in NH$_4$F, showing charge transfer and providing direct evidence of hydrogen bond formation.

Contribution

It introduces Compton scattering as a novel method to directly observe hydrogen bonds in NH$_4$F, supported by theoretical calculations.

Findings

Significant charge transfer in NH$_4$F detected

Direct proof of hydrogen bond formation

Comparison with NH$_4$Cl highlights unique bonding features

Abstract

In order to probe electron wave functions involved in the bonding of NH$_4$F, we have performed Compton scattering experiments in an oriented single crystal and in a powder. Ab initio calculations of the Compton profiles for NH$_4$F and NH$_4$Cl are used to enlighten the nature of the bonds in the NH$_4$F crystal. As a consequence, we are able to show significant charge transfer in the ammonium ion which is not observable using other methods. Our study provides a compelling proof for hydrogen bond formation in NH$_4$F.