Cationic and Anionic Impact on the Electronic Structure of Liquid Water
Yin, Z., Inhester, L., Veedu, S. T., Quevedo, W., Pietzsch, A., Wernet, P., . . . Techert, S. (2017). Cationic and Anionic Impact on the Electronic Structure of Liquid Water. Journal of Physical Chemistry Letters, 8 (16), 3759-3764. doi:10.1021/acs.jpclett.7b01392
Published inJournal of Physical Chemistry Letters
© 2017 American Chemical Society. This is a final draft version of an article whose final and definitive form has been published by ACS. Published in this repository with the kind permission of the publisher.
Hydration shells around ions are crucial for many fundamental biological and chemical processes. Their local physicochemical properties are quite different from those of bulk water and hard to probe experimentally. We address this problem by combining soft X-ray spectroscopy using a liquid jet and molecular dynamics (MD) simulations together with ab initio electronic structure calculations to elucidate the water–ion interaction in a MgCl2 solution at the molecular level. Our results reveal that salt ions mainly affect the electronic properties of water molecules in close vicinity and that the oxygen K-edge X-ray emission spectrum of water molecules in the first solvation shell differs significantly from that of bulk water. Ion-specific effects are identified by fingerprint features in the water X-ray emission spectra. While Mg2+ ions cause a bathochromic shift of the water lone pair orbital, the 3p orbital of the Cl– ions causes an additional peak in the water emission spectrum at around 528 eV. ...