Geoff Hutchison is the 2018 Tina and David Bellet Excellence Awardee. The award recognizes his effectiveness and his innovations in teaching. Among many innovations Hutchinson developed Avagadro molecular editor; with that software, he designed projects hat allow Physical Chemistry students to perform quantum mechanical calculations to visualize results/concepts.
PQI Members Sergey Frolov, David Pekker, Noa Marom, Michael Hatridge, Benjamin Hunt, and Hrvoje Petek featured on Pitt Website for their accomplisment on landing $4.8M award from National Science Foundation (NSF) for International Research and Education (PIRE) program.Sergey Frolov will be the Director of new PIRE. Hrvoje Petek, Michael Hatridge and David Pekker are other PQI co-PIs for this project. The duration of the program is 5 years.
Kevin Chen and team have demonstrated that the behavior of particles of light can be made to match predictions about the four-dimensional version of the "quantum Hall effect"—a phenomenon that has been at the root of three Nobel Prizes in physics—in a two-dimensional array of "waveguides."
“For the first time, physicists have built a two-dimensional experimental system that allows them to study the physical properties of materials that were theorized to exist only in four-dimensional space"
Recently, Tevis D. B. Jacobs and colleagues have shown how silicon- and oxygen-containing hydrogenated amorphous carbon (a-C:H:Si:O) coating enhance the thermal stability in vacuum, but tremendously increases the thermo-oxidative stability and the resistance to degradation upon exposure to the harsh conditions of low Earth orbit (LEO). These findings provide a novel physically-based understanding of the superior stability of a-C:H:Si:O in harsh environments compared to a-C:H.
The recently published paper in journal of ACS NANO on Ultrafast Microscopy of Spin-Momentum Locked Surface Plasmon Polaritons is an essential research for designing optical elements to control spin-polarized SPP (surface plasmon polaritons) fields on the nano femto scale. Hrvoje Petek and his colleagues have shown two-photon photoemission electron microscopy images formed by coupling and propagation of longitudinal and transverse components of SPP fields of light. Further, they have also shown the spin-momentum locked SPP wave packets launched with circularly polarized excitation propagate at the same phase and group velocities as for the linearly polarized excitation using time-resolved experiments.
Lillian Chong and her colleagues have recently reported, in the Journal of Nature Communications, a computational design strategy in synergistic combination with biophysical experiments to rationally improve the response time of an engineered protein-based Ca2+-sensor in which the switching process occurs via mutually exclusive folding of two alternate frames. This strategy identifies mutations that increase switching rates by as much as 32-fold, achieving response times on the order of fast physiological Ca2+ fluctuations. This computational design strategy is general and may aid in optimizing the kinetics of other protein conformational switches.
Boiling is a key heat transfer process for a variety of power generation and thermal management technologies. The enhancement in both the critical heat flux (CHF) and the critical temperature at CHF of the substrate and effectively increase the limit of boiling before the boiling crisis is triggered. By using only nanopillars with a systematic variation in height and well-defined geometrical dimensions, Paul W. Leu and colleagues have established a direct link between the enhancement in capillary force and the boiling performance of a substrate. This provides new insights about design of surface textures not only to amplify the heat flux, but also to achieve an enhancement in the temperature at critical heat flux. These results are published in Scientific Reports.
Giannis Mpourmpakis and his students have proposed a bond-centric (BC) model able to capture cohesive energy trends over a range of monometallic and bimetallic nanoparticles and mixing behavior (excess energy) of nanoalloys, in great agreement with DFT calculations. This model utilizes to calculate the energetics of any nanoparticle morphology and chemical composition, thus significantly accelerating nanoalloys design. This work introduces a simple yet very powerful tool for nanoalloy design that can potentially help elucidate the energetics of alloy MNP genomes.
Michael Widom and his colleagues showed what happens at the grain boundaries of one particular alloy of the metals nickel and bismuth that makes it brittle in their paper published in Science. Using advanced electron microscopes, Widom’s collaborators at Lehigh University scrutinized these microscopic grain boundaries at an atomic level. In a "very heroic experimental program" they discovered that when grains met, the bismuth and nickel atoms realigned into lattices to form layered superstructures at the grain boundaries. These superstructures had previously been thought to exist only rarely in some alloys. Finding it at many different boundaries led the team to conclude that these superstructures are probably much more common than many people had thought.
Owing to high surface to volume ratios and chemical potential, nanoparticles possess unique optical, electrical, and thermal properties, which constitute the basis of novel applications in sensing, catalysis, nanoelectronics, bio-tagging etc. Despite the great advances in the synthesis, the total structure determination of nanoclusters still remains to be a major challenge. Recently Hyung J. Kim and their colleagues have reported the synthesis and crystal structure of a nanocluster composed of 23 silver atoms capped by 8 phosphine and 18 phenylethanethiolate ligands in the journal of Nature Communications.