Geraldine Richmond Reflects on Her Research and NYSAS Gold Medal Win

The Gold Medal Award of the New York/New Jersey Section of the Society for Applied Spectroscopy (NYSAS), established in 1952, recognizes individuals who have made significant contributions to the field of Applied Spectroscopy and who have positively influenced the careers of others. The recipient of the 2025 NYSAS Gold Medal Award is Geraldine L. Richmond, Presidential Chair in Science and Professor of Chemistry at the University of Oregon.

Richmond’s research focuses on the molecular behavior of complex liquid interfaces, using laser-based spectroscopy and theoretical methods. Her work has contributed to a better understanding of processes relevant to atmospheric chemistry, energy science, and environmental remediation. Her studies have addressed interfacial interactions involving water, oil, surfactants, and environmentally significant molecules.

Beyond her research, Richmond has worked to promote career development and equity in science. As the founding director of the Committee on the Advancement of Women Chemists (COACh), she has led programs aimed at supporting the professional advancement of scientists and engineers, particularly women, in the U.S. and internationally. She has received multiple recognitions, including the National Medal of Science.

The 2025 Gold Medal Award Symposium will take place at the Eastern Analytical Symposium, November 17–19, at the Crowne Plaza Conference Center in Plainsboro, NJ.

As someone who also received the NYSAS Gold Medal in a previous year, I’ve had the honor of engaging with many leaders in the spectroscopy community. This interview is a bit of a full-circle moment for me—one Gold Medal recipient speaking with another. It’s a chance to explore the work of a fellow scientist whose contributions continue to shape our field in important ways.

What unique challenges arise when studying molecular interactions at the surfaces of nanoemulsions compared to planar interfaces, and how does vibrational sum frequency scattering spectroscopy (VSFSS) help overcome them? (1,2)

Since the nanoemulsions have a curved surface, many spectroscopies are not able to get that specificity unless all of the interested adsorbate is at the nanoemulsion surface and has a very strong chromophore for detection. Even in that case the question always becomes “Is it really at the surface? With VSFS, because of its surface specificity as a second-order nonlinear process the adsorbate signal can only be detected when at the surface.

However, the biggest challenge for the scattering experiment is really in the optics. The VSF signal collected in total internal reflection is already weak for a planar surface. But for the scattering experiment, you are collecting scattered sum frequency light rather than the more directional reflection beam.

Your studies highlight that neutral and charged forms of carboxylic acid surfactants behave differently at droplet interfaces. How does pH modulate the surface population of these species, and what are the implications for nanoemulsion stability? (2).

At the nanodroplet surface, a significant hydrogen-bonding interaction occurs between the headgroups at low pH that, along with hydrophobic chain–chain interactions, assists in drawing more carboxylic acid surfactant to the interface. The charged surfactant provides the stabilizing force for these droplets, while the neutral surfactant introduces complexity to the interfacial structure as the pH is lowered.

The results are significantly different than what has been found for the planar oil/water studies, where stabilization of the interface is not a factor, and we are mostly looking at molecular structure, orientation, and disorder.

In your research, how do salt-induced charge screening effects alter the adsorption behavior of ionic surfactants like sodium dioctyl sulfosuccinate (AOT) at both planar and nanoemulsion interfaces? (3).

As far as charge screening, upon addition of salts such as NaCl to the aqueous phase, it is found that AOT at both interfaces increases in surface density. We conclude from this that in the absence of added salt, the repulsive electrostatic interactions between AOT monomers are the dominant force limiting surfactant adsorption at both interfaces.

What insights have you gained from studying water combination bands in the vibrational sum frequency spectrum, especially regarding surface charge effects at oil–water interfaces? (1,5)

The spectral characteristics of this band are found to be highly sensitive to the sign and magnitude of the surface charge induced by adsorption of both anionic and cationic surfactants. The results have implications for VSF measurements of the C–H stretching vibrations of various adsorbates when studied with D₂O as the aqueous solvent. Because the vibrational signal from the water combination band is dependent on surface charge, it is imperative to include the presence of this often-ignored combination band when fitting surface spectra.

Can you explain the role of interfacial electric fields in stabilizing nanoemulsions and how these fields influence the molecular arrangement of surfactants at the droplet surface? (1,3)

The interfacial electric fields due to charge at the interface is an important stabilizing factor. This field then contributes to stronger alignment of charged headgroups at the surface of the nanoemulsions as well as the interfacial water.

Your work with multilayer polymer coatings on nanoemulsions reveals a balance of electrostatic and hydrophobic effects. How do these competing interactions influence droplet stability and polymer orientation? (4)

Our light scattering, zeta-potential, and spectroscopic results of the nanoemulsion surface show that the duration of droplet stability and the degree of molecular orientation of adsorbed polymers can be tuned by surfactant concentration, polyethylenimine (PEI) concentration, and pH. These results illustrate how molecular surface properties of multi-polymer coated nanoemulsions contribute to synergistic effects and droplet stability, enabling advancements in applications surrounding biopharmaceuticals, cosmetics and food sciences.

In complex nanoemulsion systems with multiple adsorbed species, how does VSF spectroscopy help differentiate between overlapping molecular signals at the interface? (2,5)

By deuteration of either the water, organic solvent or CH modes on the surfactants.

What structural or spectral features indicate successful surfactant or polymer adsorption in your studies, and how are these correlated with droplet longevity? (2,4)

In both planar and nanoemulsions studies, if you don’t have a stable interface, you will not see a sum frequency response since the second-order nonlinear light generation can only happen in a region where there is broken inversion symmetry, which the interface provides. Thus, for nanoemulsions, losing signal could mean instability of the droplet.

Also, there has to be a net orientation of vibrational modes of the polymer and/or surfactant at the interface to get a spectral signature for that mode. The challenge if both polymer and surfactant are adsorbed is to distinguish the signal from one and not the other.In some cases, deuteration of the surfactant provides the solution.

Given that nanoemulsions do not form spontaneously and require mechanical shear, how do you relate formation mechanisms to long-term interfacial stability in your research? (1,4)

We study them while they are stable. We haven’t done a lot of detailed studies of different durations of mechanical shear and longevity, but we have not published that.

How do your findings challenge or extend traditional models of surfactant adsorption and interfacial behavior derived from planar interface studies? (2,3,5)

It really depends up on the system. In many cases there are similarities but as the systems become more complex with polymers and mixtures, there is more deviation.

Your pioneering use of nonlinear optical spectroscopies like vibrational sum-frequency generation has revealed the behavior of water at interfaces. What has surprised you most about water’s molecular organization at air–water versus oil–water boundaries?

The weak bonding interaction between the water and the oil, which leads to water orientation which was previously not considered to happen based on theoretical studies. We conducted a whole series of experiments and confirming computational work to show how this weak bonding varies as you go from the most nonpolar organic solvent to ones with increasing yet small polarity.

How do buried liquid–liquid interfaces challenge conventional spectroscopic probing, and what experimental innovations have you introduced to overcome these obstacles?

With conventional spectroscopy and a liquid/liquid interface, the nonlinear sum frequency method comes directly from the interface whereas a linear spectroscopic method, that molecular level sensitivity is much more difficult to get. The tradeoff is that the sum frequency vibrational signal is orders of magnitude lower than, for example a linear reflection measurement. Our contribution to the field has been to conduct the experiment in a total internal reflection geometry. This has allowed us much success in a multitude of studies of adsorption at the planar oil-water interface by providing an increase in several orders of magnitude increase in an otherwise weaker sum frequency signal.

You've explored atmospheric species at air–water interfaces using vibrational spectroscopy. How do these surface studies inform our understanding of global climate models or pollutant transport?

They can help in providing data of molecular interactions at water surfaces in clouds, which has been difficult to include in atmospheric modelling. For pollutant transport, our studies of sulfur containing compounds are important, particularly the behavior of SO₂ at surfaces.

In your transition from academic research to your role at the Department of Energy (DOE), how did your knowledge of interface chemistry and spectroscopy shape your science policy priorities?

It didn’t really alter any of my priorities. It did assist me in having a deeper understanding of topics that were of interest to DOE, or were being considered for funding, that related to optics and surface science.

As a former recipient of both the Coblentz Award and the National Medal of Science, how have your spectroscopy discoveries translated into real-world applications such as environmental remediation or sustainable energy?

Our work overall mostly provides fundamental knowledge that can be useful for example in developing safer surfactants for remediation of oil spills for example, and in the nanoemulsion areas, the molecular mechanisms for polymer/surfactant coated nanoemulsions for drug delivery. Our earlier work with spectroscopic studies of gallium arsenide and silicon surfaces have relevance solar energy applications.

Your research spans decades and includes the development of computational models alongside spectroscopy. How has the synergy between theory and experiment changed in your lab over the years?

It has been very important in many of our studies and in more important ways than I had imagined. We were one of the first groups to combine VSFS with modeling and the first group to do detailed studies using the computational and spectroscopic work to confirm the weak interactions at the oil-water interface. The same can be said of our atmospheric studies where we led the field in this approach and others followed. Our approaches to the modelling have become more sophisticated with time.

In your studies of nanoemulsion stability, what spectroscopic signatures indicate successful surface stabilization, and how might these findings impact formulations in areas like drug delivery?

First, we wouldn’t get a spectroscopic signature if they weren’t stable. However, equally important were our electrophoretic mobility measurements and surface pressure measurements. The findings are important as they give a molecular picture of adsorption of polymers and surfactants that can help in the prediction of the stability of different combinations of surfactant and polymer mixtures.

The Committee on the Advancement of Women Chemists (COACh) has impacted thousands of women scientists globally—how would you describe that work?

The work of COACh has been transformative. It’s not just about professional development—it’s about creating lasting structural change. By offering training, mentoring, and leadership support, COACh has helped thousands of women scientists gain the tools and confidence to succeed and lead. What stands out to me is how they’ve expanded their efforts globally, adapting their programs to support women in diverse cultural and institutional contexts. Their impact reaches far beyond individual careers—it strengthens the entire scientific enterprise by making it more inclusive and equitable.

You've served as President of Sigma Xi, a Science Envoy, and a leader in AAAS and ACS. How can the spectroscopy community better engage in international science diplomacy and public policy?

It is important to keep lines of communication and collaboration with international colleagues.As far as public policy issues, our scientific community could do better at informing our students that public policy careers can also be a very rewarding career options beyond an academic, industrial or government laboratory career. In my recent position as Undersecretary for Science and Innovation I got to work with some of the brightest scientists that I have ever worked with, who chose science policy as their career path.

After decades in surface chemistry and spectroscopy, what unsolved questions still keep you curious at the interface?

How to get the public to understand how important light itself is as a tool for understanding the world around us—and the prevalence and importance of surfaces are in our everyday life.

References

(1) Altman, R.; Richmond, G. L.; Tran, E.; Carpenter, A. P.; Foster, M. J.; Jones, K. J.; Cano, G.; Moore, F.; Scatena, L. F. Surface Charge at an Oil/Water Interface Promoting the Enhancement and Assignment of Water Combination Bands; Univ. of Oregon: Eugene, OR, 2024. DOI: 10.2172/224665

(2) Foster, M. J.; Carpenter, A. P.; Richmond, G. L. Dynamic Duo: Vibrational Sum Frequency Scattering Investigation of pH-Switchable Carboxylic Acid/Carboxylate Surfactants on Nanodroplet Surfaces. J. Phys. Chem. B 2021, 125 (33), 9629–9640. DOI: 10.1021/acs.jpcb.1c05508

(3) Carpenter, A. P.; Foster, M. J.; Jones, K. K.; Richmond, G. L. Effects of Salt-Induced Charge Screening on AOT Adsorption to the Planar and Nanoemulsion Oil–Water Interfaces. Langmuir 2021, 37 (29), 8658–8666. DOI: 10.1021/acs.langmuir.0c03606

(4) Tran, E.; Mapile, A. N.; Richmond, G. L. Peeling Back the Layers: Investigating the Effects of Polyelectrolyte Layering on Surface Structure and Stability of Oil-in-Water Nanoemulsions. J. Colloid Interface Sci. 2021, 599, 706–716. DOI: 10.1016/j.jcis.2021.04.115

(5) Altman, R. M.; Richmond, G. L. Twist and Stretch: Assignment and Surface Charge Sensitivity of a Water Combination Band and Its Implications for Vibrational Sum Frequency Spectra Interpretations. J. Phys. Chem. B 2021, 125 (24), 6717–6726. DOI: 10.1021/acs.jpcb.1c03408

(6) Wikipedia Geraldine L. Richmond Page. Available at: https://en.wikipedia.org/wiki/Geraldine_L._Richmond

(7) Geraldine L. Richmond, University of Oregon Page. Available at: https://richmondscience.uoregon.edu/wp-content/uploads/2021/11/RichmondCV11-2021.pdf

(8) (1) Society for Applied Spectroscopy, The Early Years of SAS Home Page. Available at: https://www.s-a-s.org/assets/Early_years.pdf (accessed 2025-05-07).

(9) Society for Applied Spectroscopy, SAS History Home Page. Available at: https://www.s-a-s.org/history (accessed 2025-05-07).

(10) The New York / New Jersey Section of the Society for Applied Spectroscopy, NYSAS GOLD MEDAL AWARD Home Page. Available at: https://nysas.org/past-gold-medal-winners/ (accessed 2025-05-07).

Origins and Legacy of the NYSAS Gold Medal Award

The New York Section of the Society for Applied Spectroscopy (NYSAS) played a foundational role in both the advancement of spectroscopy and the establishment of a national professional society dedicated to the field. Emerging during World War II, the New York group formed in 1945 to support the growing number of scientists using spectroscopy for industrial applications, many of whom lacked close ties to larger professional organizations like the American Chemical Society (ACS) and the American Physical Society (APS) (8–10).

By 1956, regional groups, led in part by the New York Section, collaborated to create the Federation of Spectroscopic Societies. Two years later, in a pivotal act of cooperation, the New York Section relinquished its name and journal—Applied Spectroscopy—to help found the national Society for Applied Spectroscopy (SAS) at the first Eastern Analytical Symposium in 1958 (8,9).

Before the national society’s founding, the New York Section had already established its leadership by creating the SAS Gold Medal Award in 1952. As the first major honor in the field, it recognized lifetime achievements in spectroscopy. Early recipients included luminaries such as William F. Meggers, William W. Coblentz, and George R. Harrison. The award continues to represent the highest distinction in applied spectroscopy today (10).

About the Interviewee

Geraldine L. Richmond currently serves as the Presidential Chair in Science and Professor of Chemistry at the University of Oregon. Bridging the fields of chemistry and physics, Richmond’s research focuses on using nonlinear spectroscopic and computational studies to understand the molecular characteristics of water surfaces, studies relevant to environmental issues such as oil remediation and atmospheric chemistry. Her teaching and extensive outreach efforts have focused on science communication and building a strong, inclusive workforce. She is the Founding Director of COACh, an organization that has helped over 25,000 women scientists in career advancement in the U.S. and over two dozen developing countries. Richmond most recently has served as Undersecretary for Science and Innovation in the Department of Energy (From 2021 to 2025). Richmond has received numerous honors and awards for her research and outreach efforts, including the National Medal of Science from President Obama (2016), the Priestley Medal, American Chemical Society (2018) and the Linus Pauling Medal (2018).

About the Interviewer

Jerome Workman, Jr., serves on the Editorial Advisory Board of Spectroscopy and is the Executive Editor for LCGC and Spectroscopy. He is the co-host of the Analytically Speaking podcast and has published multiple reference text volumes, including the three-volume Academic Press Handbook of Organic Compounds, the five-volume The Concise Handbook of Analytical Spectroscopy, the 2nd edition of Practical Guide and Spectral Atlas for Interpretive Near-Infrared Spectroscopy, the 2nd edition of Chemometrics in Spectroscopy, and the 4th edition of The Handbook of Near-Infrared Analysis. He is the recipient of the 2020 NYSAS Gold Medal Award (with Howard L. Mark). Author contact: JWorkman@MJHlifesciences.com ●