Tags: Physical Seminar

We show that the continuum behavior in the variation of the X-H stretch from blue- to red- through zero- shifting observed in H-Bonds also holds good for X-Z stretch in X-Z---Y complexes where Z = a main group fragment. This has been studied by ab-initio electronic structure calculations using Z= Hydrogen, Halogens, Chalcogens and Pnicogens as prototypical examples. Our analysis revealed that, the competition between negative hyperconjugation…
Thermophoresis is a phenomenon that describes the movement of particles when a temperature gradient is present. Intuitively, when a force is acted upon a particle, we may think that the particle moves from a hot region to a cold region. However, this is not always the case. Therefore, the behavior of thermophoretic behavior is puzzling. This seminar will focus on the dominant perspectives in solution thermophoresis and how temperature and…
Nanoparticles continue to be widely studied due to their many properties and applications.  Ultra-small inorganic clusters comprised of aluminum and phosphorus were produced using a laser desorption time-of-flight mass spectrometer (LD-TOF MS).  Samples were pressed pellets as opposed to the typical thin films.  Observed clusters had electron counts which correspond to the “closo,” “nido,” and “arachno” polyhedral structures…
The ephemeral Criegee intermediate, first postulated over 70 years ago, has only recently been isolated in the gas phase. The sulfur analog of this canonical zwitterion, thioformaldehyde S-sulfide, has eluded similar analysis; however, argon matrix isolation has been achieved. In the present research, thioformaldehyde S-sulfide and its valence isomer dithiirane are examined with high-level electronic structure methods, including the minimum…
Improvements in the production of biobutanol have sparked expanded interest in its viability as a commercially utilized fuel additive.  However, the carcinogens formaldehyde and acetaldehyde are undesirable byproducts of butanol combustion. Through the use of high-level quantum chemical methods, the mechanism by which these byproducts are created can be explored to a high degree of accuracy.  Insights gleaned from these specific…
With the development of X-ray Free Electron Lasers (XFEL), new techniques for studying ultrafast chemical dynamics have been established. These experiments can provide dynamic and structural information with femtosecond temporal and angstrom spatial resolution. The electrocyclization of 1,3- cyclohexadiene is a model system for many photoinduced reactions such as production of vitamin D3 or photochromic optical switches. The previous studies of…
Coulomb Crystals, formed from laser cooling of atomic ions, have become a selective way of measuring spectroscopic transitions, kinetics and dynamics of cold ion-molecule reactions. For accurate measurements, reactants and detection methods must be state-selective. This fairly new technique has the potential to provide insight into state-to-state ion-molecule reaction dynamics provided advances in product detection are made. A background of this…