logo Pearson Lab, Department of Chemistry, Tufts University, Medford, MA 02155
  logo Shultz Laboratory for Water and Surface Analysis  
  logo  
 

Graduate Student Positions Available

Graduate Accomplishments!


(Top Left) A photomicrograph of the secondary prism face of ice shows a dark ridge reflecting the molecular-level structure of that face. (Top Right) A tube model of the secondary prism face shows protruding ridges. (Bottom) A side view of the dimers that run along the ridges of the secondary face.
Recent graduates have made discoveries both with respect to the inner workings of the hydrogen bond and in controlling charge flow in photocatalytic reactions.

The most recent work at Tufts University focuses on icy surfaces and on clathrate formation. Probing the ice surface begins with a well-prepared single-crystal. We have unique capabilities for growing single-crystal ice from the melt and for and preparing any desired ice face (timeframe is weeks compared with decades with previous methods!). Results show that the growing ice-water interface is not the expected basal face – reflected in the familiar hexagonal shape of snowflakes – but rather the secondary prism face – the thin snowflake edge. Following in the footsteps of Pauling, we developed a statistical mechanical model that explains this observation. (J. Phys. Chem. B 2014, 118, 7972. http://dx.doi.org/10.1021/jp500956w) The secondary prism face features water molecule dimers – visualized as a ridge in the photomicrograph at the right. A recent graduate discovered these dimers and their isolated vibrational resonances; resonances that reveal both nearest neighbor and longer range interactions. (J. Chem. Phys. 2014, 141, 18C521. http://dx.doi.org/10.1063/1.4896603) Pilot work indicates that the thin edge is catalytic for many atmospheric transformations.

In this work, students not only designed and built the ice growing apparatus they also created new spectroscopic methodology. Current students are finalizing a unique nonlinear spectrometer that promises to both be more sensitive to low concentration species at the surface and to provide unique insights into the resonances that underlie the congested hydrogen-bonded spectrum. The watershed feasibility studies are complete, thus new students have a fantastic opportunity to join this work as it is taking off!

Clathrates are a fascinating application of hydrogen bonding. Methane clathrates in the environment contain as much carbon as all the oil so far discovered on Earth! Clathrates potentially provide a condensed-phase means for transporting gaseous energy carriers such as hydrogen or light hydrocarbons but for one issue: they normally require extreme pressure (tens to nearly a thousand atmospheres). So called helper gases can lower the pressure requirement. Recent students developed a novel matrix isolation method to probe helper-gas interactions and discovered a synergistic polarization modification that provides insight into helper gas function. (J. Phys. Chem. B 2014, 118 ASAP http://dx.doi.org/10.1021/jp509343x) Guided by these principles, a recent student discovered a helper gas that works at atmospheric pressure! The same synergistic polarization modification is involved in protein folding. Environmental and biological processes are connected via water.

We often take clean water for granted. Millions of people around the world are not so blessed. Half the world’s hospital beds are occupied by people suffering from illnesses directly attributable to lack of safe drinking water. The goal of our clean water research is to devise a photocatalyst that can capture readily available sunlight and use the energy to turn pollutants into CO2 and water. A photocatalyst works by separating charge, ultimately transferring electrons or hydrogen atoms from a pollutant to molecular oxygen. Well before it became popular, past students focused on making the charge transfer to oxygen step more efficient. Recent graduates have discovered methods to make very small photocatalyst particles and modify or dope them to enhance the charge transfer step. The result is a whopping three-fold increase in photo efficiency. To be a viable photocatalyst, that efficiency merely needs another factor of two improvement. Current students are working on this problem; new students will join them and work on the last step. That last step involves immobilizing the particles on a transparent substrate thereby eliminating the need to separate particles from the clean water produced. There is an opportunity to get in on the ground floor of the immobilization work and make a difference in the lives of millions of people.

Opportunity for growth: As is common in physical chemistry, many of the scientific instruments were designed and built by recent graduates. New students have the opportunity to expand their expertise and talents. For example, our SFG spectroscopy system has many features not commercially available that were designed and built in-house. Current students are developing techniques that enable fully complex signal analysis supporting greater precision and accuracy than any currently in use. Many of our custom designed instruments require software control. For example our SFG instrument incorporates a large scale LabVIEW application, developed and written by a recent graduate student. Graduate students working on the clean water project developed synthetic procedures capable of producing very small (about 2nm dia.) nano particles with very low size dispersion and high crystalline purity. These protocols also yield nano particles with precisely controlled surface chemistry that is key in the charge transfer processes mentioned above.

Ideal candidates are not only interested in the chemistry, but also are interested in technical aspects of doing scientific research. Individuals with talent or interest in any of the following areas– lasers (pulsed and CW), optics (geometric and non-linear), physics (heat transport, thermodynamics), mechanical design (2D and 3D CAD), software development (LabVIEW), electronics (fabrication and design), machine shop, glass blowing (we have our own lab!), cryogenic apparatus design and construction are particularly encouraged. A double major undergraduate degree is a plus.

If you're interested in any or all of these topics and you're serious about learning to be a scientist of the highest caliber, contact Prof. Mary Jane Shultz as indicated below:

Professor Mary Jane Shultz
Tufts University
Department of Chemistry
Fred Stark Pearson Laboratory
62 Talbot Avenue
Medford, MA 02155
Office: P-100D
email: mary.shultz@tufts.edu
Phone: 617-627-3477 FAX: 617-627-3443
Dept. Web Page: http://chem.tufts.edu/faculty/shultz
Research Home Page: http://ase.tufts.edu/chemistry/shultz

   
  © Copyright 2017, Department of Chemistry, Tufts University. All rights reserved. Website designed and maintained by Tufts Technology Services (TTS).