Tribute to Veronica Vaida - ACS Publications - American Chemical

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Special Issue Preface Cite This: J. Phys. Chem. A 2018, 122, 1157−1158

pubs.acs.org/JPCA

Tribute to Veronica Vaida Published as part of The Journal of Physical Chemistry virtual special issue “Veronica Vaida Festschrift”. role of water in the catalysis and/or suppression of reactions of chromophores involved in radical chemistry. Her work on photochemistry with solar (red) light has provided a fundamentally new paradigm in which photochemical reactions may occur in a concerted fashion on the ground state potential surface, leading to reaction products akin to those from thermally activated reactions, but at ambient temperatures. For example, she showed that the vibrational overtone pumping chemistry of sulfuric acid leads to its dehydration, which carries important consequences relating to aerosol formation and the SO2 vertical profile in Earth’s atmosphere. This chemistry is now being used to understand the measured sulfur chemistry on Venus (as observed by the Venus Explorer). More recently, her group has shown elegant examples of such concerted photochemical reactions occurring in organic acids and alcohols. Another important research topic first articulated and explored by Veronica is the effect of water on thermal and photochemical reactions of importance to the atmosphere. Due to its strong hydrogen-bonding propensity, water molecules may play an important role in binding to atmospheric molecules, thereby potentially changing the chemical and photochemical pathways available. Her group has investigated the effect of water vapor and small water clusters on the chemistry and the energetics of several reaction mechanisms, thus providing important information on energy flow in molecules. The properties of atmospheric aerosols relevant to climate and chemistry are highly nonlinear, resulting in large uncertainties in aerosol effects that impact the Earth’s climate. Inspired by atmospheric measurements which have established that aerosols have a large organic content, Veronica and her collaborators proposed that a significant population of organic aerosols consists of an aqueous core with an organic surface film, which has profound consequences for the morphology, optical, and chemical properties. She showed that organics coat atmospheric aerosols and has investigated the fundamental physical chemistry of interfacial organic films using Langmuir−Blodgett techniques. Veronica then extended the surfactant-coated aerosol model to the prebiotic atmosphere, positing their possible role in the origin of life. Most recently, Veronica has investigated the aqueous interface as a catalyst for life. In protein formation, amino acids join together to form peptide bonds. The emergence of life certainly depended on this process, but without a biological protein builderthe ribosomeprotein formation in aqueous environments is thermodynamically unlikely. To unravel this enigma, Veronica investigated peptide bond formation at the water’s surface, where the air−water interface creates a unique environment for chemical reactions. This work showed that the water− air interface encouraged peptide bond formation by restricting the amount of available water, altering the electronic characteristics of compounds on the surface, and concentrating and aligning the amino acid building blocks. The results bring us a

Photo by Kathleen Human Photo by Kathleen Human

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ver her career, Professor Veronica Vaida has made significant and important contributions to our understanding of fundamental chemical processes. During the past 30 years, Veronica’s research, teaching, and service have placed her chemistry in the context of central problems that impact society, namely, climate change and air quality, and have addressed many questions surrounding the way in which important biochemicals were formed in a prebiotic time. Her career is marked by creative, bold moves and has followed a trajectory of increasing chemical complexity. At the start of her independent career, Veronica’s research focused on understanding reactivity using the electronic spectroscopy and photodissociation dynamics of small, gas phase molecules. She developed the technique of UV/visible direct absorption spectroscopy of molecules cooled in supersonic jets and used this method to probe the structure and dynamics of the electronically excited states of organic molecules. She also pioneered a route to bare transition metal ions and clusters by multiphoton dissociation of organometallic complexes. Later, she used the direct absorption and other spectroscopic techniques to study the excited state photodissociation dynamics of a range of small reactive molecules, including OClO and NH3. Later in her career, her research efforts were at the interface of physical chemistry and atmospheric science, where she brought her creativity to bear on new ideas concerning waterand sunlight-mediated processes in planetary atmospheres including contemporary and prebiotic Earth. In the atmospheric arena, she provided fundamental mechanisms to problems where discrepancies between observations and models pointed to a fundamental knowledge gap. On the basis of observations termed “anomalous cloud absorption”, Veronica proposed that water complexes are important in radiative transfer and thus necessary in predictive models of climate. In response to observations of high HOx radical concentrations with the Sun near the horizon, Veronica used O−H overtones to drive reactions significant in the atmosphere and pointed to the © 2018 American Chemical Society

Published: February 8, 2018 1157

DOI: 10.1021/acs.jpca.7b11829 J. Phys. Chem. A 2018, 122, 1157−1158

Special Issue Preface

The Journal of Physical Chemistry A little closer to understanding how basic building blocks may have assembled to form life’s complex molecules and, further, underscores the importance of orientation, alignment, and proximity in modern ribosomal peptide bond synthesis. In summary, Veronica Vaida uses fundamental physical chemistry to address complex problems ranging from the detailed dynamics of small molecules to understanding atmospheric chemistry of the Earth and other planetary systems to the origins of life. She has a keen sense for identifying important problems, and often her research provides fundamental insights where measurements and models disagree. Her work is highly innovative and she has demonstrated time and time again that there are enormous benefits to society in understanding the fundamental physical chemistry of molecular systems. Her excitement about the field of chemistry is apparent in everything she does. She is the consummate academic chemistimpacting her colleagues, students, and the profession in a multitude of ways. We would be remiss if we did not note that not only is Veronica an amazing chemist, but also she is a kind, caring, and generous person. All we can say is “thank you Veronica” for all that you do, for all that you are, and most importantly, for making this profession and this world a better place.

D. James Donaldson University of Toronto

Joseph S. Francisco University of Nebraska

Vicki H. Grassian University of California San Diego

Russell J. Hemley George Washington University

David M. Jonas University of Colorado

Kenneth R. Leopold University of Minnesota

Nancy E. Levinger

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Colorado State University

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpca.7b11829. Table of Contents for the Veronica Vaida Festschrift (PDF)

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DOI: 10.1021/acs.jpca.7b11829 J. Phys. Chem. A 2018, 122, 1157−1158