ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
060421_CMPL.pdf (2.38 MB)

A New Imaginary Term in the 2nd Order Nonlinear Susceptibility from Charged Interfaces

preprint
submitted on 06.04.2021, 21:36 and posted on 07.04.2021, 12:25 by Emily Ma, Jeongmin Kim, Yangdongling Liu, Emilie Lozier, Thomas Miller, Hongfei Wang, Franz Geiger, Paul ohno

Non-resonant second harmonic generation phase and amplitude measurements obtained from the silica:water interface at varying pH and 0.5 M ionic strength point to the existence of a nonlinear susceptibility term, which we call , that is associated with a 90° phase shift. Including this contribution in a model for the total effective second-order nonlinear susceptibility produces reasonable point estimates for interfacial potentials and second-order nonlinear susceptibilities when . A model without this term and containing only traditional and terms cannot recapitulate the experimental data. The new model also provides a demonstrated utility for distinguishing apparent differences in the second-order nonlinear susceptibility when the electrolyte is NaCl vs MgSO4, pointing to the possibility of using HD-SHG to investigate ion-specificity in interfacial processes.

History

Email Address of Submitting Author

f-geiger@northwestern.edu

Institution

Northwestern University

Country

USA

ORCID For Submitting Author

0000-0001-8569-4045

Declaration of Conflict of Interest

n.a.

Version Notes

Pre-edited version, 16 pages main text, 4 figures, Supporting Information.

Exports