Title:	The molecular structure of the surface of water–ethanol mixtures
Authors:	Kirschner, Johannes Gomes, Anderson H. A. Marinho, Ricardo dos Reis Teixeira Björneholm, Olle Ågren, Hans Carravetta, Vincenzo Ottosson, Niklas Brito, Arnaldo Naves de Bakker, Huib J.
Assunto::	Estrutura molecular Água Etanol
Issue Date:	11-May-2021
Publisher:	Royal Society of Chemistry
Citation:	KIRSCHNER, Johannes et al. The molecular structure of the surface of water–ethanol mixtures. Physical Chemistry Chemical Physics, n. 23, p. 11568–11578, 2021. Disponível em: https://pubs.rsc.org/en/content/articlelanding/2021/cp/d0cp06387h. Acesso em: 03 maio 2022.
Abstract:	Mixtures of water and alcohol exhibit an excess surface concentration of alcohol as a result of the amphiphilic nature of the alcohol molecule, which has important consequences for the physicochemical properties of water–alcohol mixtures. Here we use a combination of intensity vibrational sum-frequency generation (VSFG) spectroscopy, heterodyne-detected VSFG (HD-VSFG), and core-level photoelectron spectroscopy (PES) to investigate the molecular properties of water–ethanol mixtures at the air–liquid interface. We find that increasing the ethanol concentration up to a molar fraction (MF) of 0.1 leads to a steep increase of the surface density of the ethanol molecules, and an increased ordering of the ethanol molecules at the surface. When the ethanol concentration is further increased, the surface density of ethanol remains more or less constant, while the orientation of the ethanol molecules becomes increasingly disordered. The used techniques of PES and VSFG provide complementary information on the density and orientation of ethanol molecules at the surface of water, thus providing new information on the molecular-scale properties of the surface of water–alcohol mixtures over a wide range of compositions. This information is invaluable in understanding the chemical and physical properties of water–alcohol mixtures.
Licença::	Physical Chemistry Chemical Physics - For all articles published in our journals, we require the author to accept a 'licence to publish'. This licence is normally requested after their article is accepted for publication. By signing this licence the author (who is either the copyright owner or who is authorised to sign on behalf of the copyright owner, for example his/her employer) grants to the Royal Society of Chemistry the exclusive right and licence throughout the world to edit, adapt, translate, reproduce and publish the manuscript in all formats, in all media and by all means (whether now existing or in future devised). FONTE: https://www.rsc.org/journals-books-databases/author-and-reviewer-hub/authors-information/licences-copyright-permissions/#about-licence. Acesso em: 03 maio 2022.
DOI:	https://doi.org/10.1039/d0cp06387h
metadata.dc.relation.publisherversion:	https://pubs.rsc.org/en/content/articlelanding/2021/cp/d0cp06387h
Appears in Collections:	Artigos publicados em periódicos e afins

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