Strong-Field Chemistry of Ions and Radicals: Ultrafast Dynamics and Nanomaterial Synthesis

Katharine Tibbetts

Department of Chemistry, Virginia Commonwealth University

Friday, January 18 at 4:00 pm in 701 W. Grace St., Room 2310

   Ionizing radiation can be destructive when it causes damage to DNA, but also can be constructive when used to synthesize novel nanomaterials without toxic chemicals. High-intensity, ultrashort (picosecond-femtosecond) laser pulses can mimic many properties of ionizing radiation such as X-rays, using visible or infrared wavelengths instead. This talk will highlight recent recent results in our laboratory using strong-field femtosecond laser pulses to induce ion chemistry. First, we will present ultrafast dynamics measurements of organophosphorus and nitrotoluene radical cations using pump-probe techniques. The organophosphorus molecules dimethyl methylphosphonate (DMMP) and trimethyl phosphate (TMP) model the DNA sugar-phosphate backbone, so their radical cation dynamics can provide insight into reaction pathways occurring in DNA upon removal of an electron from the phosphate group. The nitrotoluenes model explosives such as TNT, making their dissociation dynamics relevant to energetic material development. The ionization-induced coherent vibrational dynamics in both families of molecules will be discussed. The second part of the talk will discuss applications to nanomaterials synthesis of high-density plasmas consisting of free electrons and OH• radicals formed by focusing femtosecond laser pulses in aqueous solution. The plasma electrons can reduce metal ions in solution to form metal nanoparticles, and the hydroxyl radicals can result in accelerated particle growth or back-oxidation, depending on the target metal. We will discuss the mechanisms leading to the conversion of tetrachloroaurate ([AuCl4]-), silver nitrate (AgNO3), and copper acetate (Cu(OAc)2) to Au, Ag and Cu nanoparticles both in aqueous solution and in the presence of a silicon wafer. When silicon is present, the metal nanoparticles can be isolated in a silica matrix, which prevents their aggregation and yields ultrasmall ~2 nm particles.

VCU Department of Physics Colloquia: Fall 2018

Applications of Lithium-Ion Batteries in Electric Drive Vehicles

Tien Quang Duong 

Vehicle Technologies Office, U.S. Department of Energy

Friday, November 30 at 4:00 pm in 701 W. Grace St., Room 2310

Supathorn (Supy) Phongikaroon, PH.D., P.E.

Department of Mechanical and Nuclear Engineering, VCU

Friday, November 16 at 4:00 pm in 701 W. Grace St., Room 2310

A rapid overview of high-speed atomic force microscopy: it's impact and applications.

Dr. Loren Picco

Department of Physics, VCU

Friday, November 9 at 4:00 pm in 701 W. Grace St., Room 2310

I will provide an introduction to my research into scanning probe microscope development and instrumentation. I will go over some of the high-impact areas of research that it has been used for and then round off with some highlights of my most recent work and plans now that I am establishing my lab at VCU.

A look into the fabrication,characterization and applications of 2D hemetene.

Tyler Selden

PhD candidate in Nanoscience

VCU Department of Physics

Friday, November 2 at 4:00 pm in 701 W. Grace St., Room 2310

Personalizing cancer therapy with nanoscience tools

Graeme F. Murray

MD/PhD candidate in Nanoscience

VCU School of Medicine and Department of Physics

Friday, October 26 at 4:00 pm in 701 W. Grace St., Room 2310

Dr. Magdalena K. Morgan

VCU Innovation Gateway 

Friday, October 5 at 4:00 pm in 701 W. Grace St., Room 2310

Dr. Morgan will explain how the Innovation Gateway is helping students, faculty and researchers commercialize their inventions and creative work. She works with a team of technical professionals, business developers and administrators to guide and support VCU faculty, staff and trainees in the process of technology transfer to industry. Her talk will discuss how the Innovation Gateway conducts intellectual property evaluation and protection, technology marketing, start-up creation, and new programs to promote a culture of innovation here at VCU.

Modified Dark Matter: Relating Dark Energy, Dark Matter, and Baryonic Matter

Dr. Doug Edmonds

Department of Physics, Penn State-Hazelton 

Friday, September 28 at 4:00 pm in 701 W. Grace St., Room 2310

Modified dark matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics. For an accelerating Universe with positive cosmological constant ($\Lambda$), such phenomenological considerations lead to the emergence of a critical acceleration parameter related to $\Lambda$. Such a critical acceleration is an effective phenomenological manifestation of MDM, and is found in tight correlations between dark matter and baryonic matter in galaxy rotation curves, the so-called Mass Discrepancy Acceleration Relation (MDAR). The resulting MDM mass profiles are consistent with observational data at both the galactic and cluster scales.

Synthetic Strategies of some Nanostructured Materials

Dr. Tarek M. Abdel-Fattah

Department of Chemistry and Applied Research Center at Thomas Jefferson National Accelerator Facility and Department of Molecular Biology and Chemistry at Christopher Newport University

Friday, September 21 at 4:00 pm in 701 W. Grace St., Room 2310

Nanotechnology deals with materials with dimensions in the range of 1 nm to 100 nm. Materials in that range (1-100 nm) possess novel properties and characteristics different from bulk materials.  Therefore, nanotechnology has been of increasing interest in the last decade and used as catalysts, sensors, solar cells and in water decontamination systems. We will present the detailed insights into two synthetic strategies, bottom-up and top-down, for nanomaterials fabrication. In addition, we will report the synthesis and assembly of highly ordered multiple tube-in-tube nanostructures within porous materials.