Miriam A. Freedman

Miriam A. Freedman

Main Content

  • Assistant Professor of Chemistry
205 Chemistry Building
University Park, PA 16802
(814) 867-4267


  1. B. A., Swarthmore College, 2000
  2. M. S., University of Minnesota, 2002 (Mathematics)
  3. M. S., University of Chicago, 2003
  4. Ph. D., University of Chicago, 2008

Honors and Awards:

  1. NOAA Climate and Global Change Postdoctoral Fellowship 2008-2010
  2. NSF Graduate Fellowship 2003-2006

Selected Publications:

D. P. Veghte, M. A. Freedman, The Necessity of Microscopy to Characterize the Optical Properties of Size-Selected, Nonspherical Aerosol Particle, Analytical Chemistry, 84: 9101-9108 (2012).

R. D. Brown, Q. Tong, J. S. Becker, M. A. Freedman, N. A. Yufa, S. J. Sibener, Dynamics of Molecular and Polymeric Interfaces Probed with Atomic Beam Scattering and Scanning Probe Imaging. Faraday Discussions, 157: 307-323 (2012).

K. J. Zarzana, D. O. DeHaan, M. A. Freedman, C. A. Hasenkopf, M. A. Tolbert, Optical Properties of Oligomers Formed by Reactions of α-Dicarbonyls and Amines in Simulated Cloud Droplets, Environmental Science and Technology, 46: 4845-4851 (2012).

M. E. Wise, K. J. Baustian, T. Koop, M. A. Freedman, E. J. Jensen, M. A. Tolbert, Depositional Ice Nucleation onto Crystalline Hydrated NaCl Particles: A New Mechanism for Ice Formation in the Troposphere, Atmospherical Chemistry Physics 12: 1121-1134 (2012).

C. A. Hasenkopf, M. A. Freedman, M. R. Beaver, O. B. Toon, M. A. Tolbert, Potential climactic impact of organic haze on the Early Earth, Astrobiology, 11: 135-149 (2011). 

M. A. Freedman, K. J. Baustian, M. E. Wise, M. A. Tolbert, Characterizing the Morphology of Organic Aerosols at Ambient Temperature and Pressure, Analytical Chemistry, 82: 7965-7972 (2010).

M. R. Beaver, M. A. Freedman, C. A. Hasenkopf, M. A. Tolbert, Cooling Enhancement of Aerosol Particles due to Surfactant Precipitation, Journal of Physical Chemistry A, 114: 7070-7076 (2010).

M. A. Freedman, C. A. Hasenkopf, M. R. Beaver, M. A. Tolbert, Optical Properties of Internally Mixed Aerosols of Dicarboxylic Acids and Ammonium Sulfate, Journal of Physical Chemistry A, 113: 13584-13592 (2009).


We are interested in heterogeneous processes in the environment, and more specifically those related to atmospheric science.  Condensed matter in the atmosphere consists of aerosol particles, cloud droplets, ice crystals, and precipitation.  Our goals are to understand 1) the interaction of radiation with aerosol particles, 2) the processing of aerosol particles in the environment, and 3) the interactions between aerosol particles and clouds.  Through such studies, we can better understand the direct and indirect impacts of aerosol particles on climate, which are currently not well characterized.

From a molecular perspective, aerosol particles are exceedingly complex systems.  The longest-lived aerosols range in size from 10 nm to 10 μm, which roughly corresponds to 104 to 1013 molecules.  To fully understand the properties of aerosol particles, we need to link their molecular-level properties to their ensemble properties.  This necessitates performing experiments at different length scales.  As a consequence, we perform a range of different experiments spanning molecular, single-particle, and ensemble measurements. 

Our particular focus within the field of aerosol science is determining how surface, interfacial, and particle structure affect aerosol properties and reactivity.  On the ensemble length scale, we study the optical properties and hygroscopicity of aerosol particles using cavity ring-down spectroscopy.  We are interested in how the composition and morphology of particles affects their interaction with radiation and their ability to take up water.  To characterize the internal structure of single particles, we investigate the use of a variety of microscopy techniques for determining aerosol morphology.  Finally, we probe the surface structure and water uptake characteristics of model aerosols on the molecular scale using surface science techniques.  In addition, we use Mie scattering and other atmospheric-related theories to more broadly understand the implications of our experiments.

Research Interests:


Spectroscopy and surface science of atmospheric aerosol particles