Nicole Gonzalez

Postdoc, Chemistry – Northwestern University (2026)

Ph.D., Chemistry – Pennsylvania State University (2024)

B.S., Industrial Chemistry – University of Puerto Rico at Humacao (2019)

Research Interests

• Development of advanced nonlinear optical spectroscopic techniques
• Understanding molecular structure, water organization, and electrostatics at aqueous interfaces
• Investigating molecular interactions and adsorption of ions, proteins, nanoparticles, and other species at monolayer/water and mineral oxide/water interfaces
• Exploring the behavior of environmental contaminants and surface-active molecules

Research Description

Aqueous interfaces play an important role in many chemical, environmental, and biological processes, including ion adsorption, contaminant transport, and molecular recognition. At these interfaces, water molecules, ions, and other chemical species interact with surfaces in ways that can differ from their behavior in bulk solutions. Understanding these molecular-level interactions is essential for determining how surface chemistry and environmental conditions influence interfacial structure, electrostatics, and molecular organization.

Our research focuses on the development and application of nonlinear optical spectroscopy to investigate molecular structure and interactions at aqueous interfaces. We use surface-sensitive techniques, including phase-resolved second harmonic generation (SHG) and sum frequency generation (SFG), to study mineral/water and monolayer/water interfaces. Unlike many conventional bulk spectroscopic techniques, SHG and SFG are sensitive to interfaces because their electric-dipole responses are suppressed in centrosymmetric bulk media. Phase-resolved SHG provides quantitative information about interfacial electrostatics, while vibrational SFG allows us to investigate the molecular orientation of interfacial water.

We investigate how pH, ionic composition, concentration, temperature, and surface chemistry influence molecular interactions and interfacial properties. Our research explores ion-specific effects, surface charge regulation, and the adsorption and organization of molecules at charged interfaces. By establishing relationships between molecular structure and interfacial behavior, we aim to advance our understanding of fundamental chemical processes relevant to environmental, geochemical, and biological systems.

Selected Publications

Raiden Speelman, Nicole M. Gonzalez, Camille M. Bridgewater, and Franz M. Geiger. Second Harmonic Generation Electric Field Triplet Interferometry for Absolute Phasing. The Journal of Physical Chemistry Letters 2026 17, (6), 1687–1693.

Nicole M. Gonzalez, Amani Alghamdi, and Franz M. Geiger. Dehydration of Oxide:Water Interfaces by Brines Quantified with Nonlinear Spectroscopy. Journal of the American Chemical Society 2025 147, (36), 33273-33280.

Amani Alghamdi, Nicole M. Gonzalez, and Franz M. Geiger. Temperature Dependence of Proton Coverage and the Total Potential and at Fused Silica:Water Interfaces from Phase-Resolved Nonlinear Optics. Journal of the American Chemical Society 2025 147 (17), 14308-14315.

Kenneth D. Judd, Nicole M. Gonzalez, Tinglu Yang, and Paul S. Cremer. Contact Ion Pair Formation Is Not Necessarily Stronger than Solvent Shared Ion Pairing. The Journal of Physical Chemistry Letters 2022 13 (3), 923-930.

Honors and Awards

• International Institute for Nanotechnology Postdoctoral Fellowship, Northwestern University (2025 – 2026)
• Dalalian Continuing Graduate Student Award, The Pennsylvania State University (2024)
• Carl Storm Underrepresented Minority Fellowship, Gordon Research Conference (2022)
• Bunton Waller Graduate Student Award, The Pennsylvania State University (2019)
• Nominated for the “Best Student of Chemistry 2017” prize, awarded by the College of Chemists of Puerto Rico
• NSF-PREM Research Fellowship, University of Puerto Rico at Humacao (2016 – 2019)