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Mark Maroncelli

Emeritus, Distinguished Professor of Chemistry



Professional Appointments and Affiliations

Emeritus, Distinguished Professor of Chemistry

Associate Head for Undergraduate Education


408 Chemistry Building

University Park, PA 16802


B.A., Williams College, 1979

Ph.D., University of California, Berkeley, 1984

Honors and Awards

Joel Henry Hildebrand Award in the Theoretical and Experimental Chemistry of Liquids, 2015

Penn State Distinguished Professor, 2015

Humboldt Research Award, 2009

Fellow of the American Association for the Advancement of Science, 2008


Research in the Maroncelli group focuses on studies designed to help build a fundamental understanding of solvation and how it affects chemical reactions taking place in solution. In contrast to reactions in the gas phase, even unimolecular reactions in solution actually involve interactions with tens to hundreds of solvent molecules. The disorder inherent to the liquid state and the rapidity of the relevant dynamics makes it difficult to describe the effect of these myriad interactions in a simple and accurate way.

Our group employs spectroscopic techniques in combination with modern computational chemistry methods to help develop a molecular-level understanding of equilibrium and non-equilibrium solvation and its influence over chemistry in solution.  Experimental methods include steady-state electronic spectroscopy, ps and fs fluorescence methods, dynamic NMR measurements and teraherz spectroscopy. Molecular dynamics simulations and electronic structure methods provide the primary means for properly interpreting experimental observations in terms of molecular interactions and dynamics. Our recent work has focused on elucidating the nature of solvation in unconventional solvents such as supercritical fluids, gas-expanded liquids, and most recently ionic liquids. In these as well as in conventional solvents, prototypical reactions involving isomerization, electron transfer, and proton transfer are studied in order to test and develop our understanding of solvent - reaction coupling.

Selected Publications

Christopher A. Rumble and Mark Maroncelli, “Solvent Controlled Intramolecular Electron Transfer in Mixtures of 1-Butyl-3-Methylimidizolium Tetrafluoroborate and Acetonitrile,” J. Chem. Phys. 148, 193801 (2018).  DOI:  10.1063/1.5000727

Boning Wu, Mark Maroncelli, and Edward W. Castner, Jr., “Photoinduced Bimolecular Electron Transfer in Ionic Liquids,” J. Am. Chem. Soc. 139, 14568−14585 (2017).  DOI: 10.1021/jacs.7b07611

Christopher A. Rumble, Jens Breffke, and Mark Maroncelli, “Solvation Dynamics and Proton Transfer in Diethylaminohydroxyflavone,” J. Phys. Chem. B 121, 630-637 (2017).  DOI: 10.1021/acs.jpcb.6b12146

Christopher A. Rumble, Anne Kaintz, Sharad K. Yadav, Brian Conway, Juan C. Araque, Gary A. Baker, Claudio Margulis, and Mark Maroncelli, “Rotational Dynamics in Ionic Liquids from NMR Relaxation Experiments and Simulations:  Benzene and 1-Ethyl-3-Methylimidazolium,” J. Phys. Chem. B 120, 9450-9467 (2016).  DOI: 10.1021/acs.jpcb.6b06715

Anne Kaintz, Gary Baker, Alan Benesi, and Mark Maroncelli, “Solute Diffusion in Ionic Liquids, NMR Measurements and Comparisons to Conventional Solvents,” J. Phys. Chem. B 117, 11697–11708 (2013).  DOI: 10.1021/jp405393d

Xin-Xing Zhang, Min Liang, Nikolaus P. Ernsting, Mark Maroncelli, “The Complete Solvation Response of Coumarin 153 in Ionic Liquids,” J. Phys. Chem. B 117, 4291-4304 (2013).  DOI: 10.1021/jp305430a

Durba Roy and Mark Maroncelli, “Solvation and Solvation Dynamics in an Idealized Ionic Liquid Model,” J. Phys. Chem. B 116, 5951-5970 (2012).  DOI: 10.1021/jp301359w