Written by Nora Berrah: Debadarshini (Jolly) Mishra successfully defended her PhD thesis in May 2024 in Atomic, Molecular and Optical Physics. Jolly gave several presentations at national and international conferences and is the co-author of 8 publications. She is now a postdoc at Lawrence Berkeley National Lab and was hired before her thesis defense to […]
Bren Backhaus Advisor: Jonathan Trump Thesis: “Emission-Line Properties of High-Redshift Galaxies and their Black Holes” Dharma Basaula Advisor: Serge Nakhmanson Thesis: “Mesoscale Modeling of Thermoelectric Materials” Mitchell Bredice Advisor: Vasili Kharchenko Thesis: “Kinetics, Nucleation, and Relaxation Dynamics of Ion-Seeded Nanoparticles” Michael Davino Advisor: Carlos Trallero Thesis: “Strong-field Physics from Atoms to Nanoparticles” Ashok Gurung Advisor: […]
On August 27, 2024, scholars, trustees, and friends of UConn gathered at the University of Connecticut School of Law to honor members of the university community elected to the National Academies of Sciences, Engineering, and Medicine. Established by an Act of Congress in 1863, the National Academy of Sciences was followed by the National Academy […]
Dear Friends of UConn Physics, Last year, I wrote to you as a new Interim Head of Physics and only barely a month into my appointment. During the past year, we conducted a search for a permanent head and I was selected. For this, I am very grateful for the trust and support I received […]
Every year, the American Physical Society (APS) sponsors CU*IP – Conference for Undergraduate Women and Gender Minorities in Physics – at several locations around the country. This year, led by Prof. Nora Berrah, UConn Physics applied to host this national conference in Storrs and our proposal was accepted for January 24-26, 2025! The purpose of […]
Lawrence “Larry” Kappers, passed away on Friday, August 2, 2024. Professor Lawrence (Larry) Kappers (aka “Kap”) retired in 2009, having joined the UConn Physics Department in 1973. After receiving his Ph.D. from the University of Missouri-Columbia and completing postdoctoral appointments at the University of Minnesota and Oklahoma State University, he developed an active research program […]
The UConn STARs group visited Hartford Public High School (HPHS) to teach physics for a total of eight class periods from May 6th-9th, 2024. UConn brought 16 undergraduate students from the STARs program to HPHS for our annual outreach program, during which we interacted with about 100 high school students. We collaborated with physics teacher […]
Father Thaddeus J. Burch passed away May 14, 2024 in Wauwatosa, WI. He was 93 years old, a Jesuit for 75 years and a priest for 62 years. His life combined his deep religious faith with a quest and appreciation for the world of physics. In addition to his two bachelor’s degrees in philosophy and […]
Professor Moshe Gai, the director of the Laboratory for Nuclear Science, aka the Astrophysics Laboratory, https://astro.uconn.edu, was awarded a 2024-2025 Fulbright US Scholar Award to teach and do research in Romania. He will spend five months at the newly constructed world highest power laser lab (10 PW), the Extreme Light Infrastructure Nuclear Physics (ELI-NP), recently […]
The University of Connecticut, Department of Physics is proud to announce the 26th Annual Katzenstein Distinguished Lecturer that will be on Friday, November 15th.
UConn physics professor Nora Berrah has been elected as a member of the National Academy of Science (NAS), becoming the fifth member from the UConn community to join the selective national society.
Connecticut’s oldest planetarium will soon be back in action. Once used for education and outreach for UConn faculty, students, and community members, the planetarium fell into disuse in the last several years, but Department of Physics Assistant Professor-in-Residence Matt Guthrie has been working hard with skilled facilities staff, including CLAS Facilities Team Leader Brett DeMarchi, to bring this piece of UConn history back into working order.
Two of UConn Physics Department’s undergrads, Rachel Cleveland and Nicholas Thiel-Hudson, have been recently selected as part of the 2024 cohort of UConn University Scholars! These students were selected based on the strength of their proposal. Graduation as a University Scholar recognizes a student’s extraordinary engagement with self-reflective learning and research or creative endeavors.
After years of disuse, the UConn Observatory, featuring a 16-inch optical telescope, is coming back into service. Physics faculty member Matt Guthrie, a driving force behind this rejuvenation effort spoke with UConn Today about the benefits offered by the Observatory both to students and to the community.
On October 14, 2023 40-50 members and friends of the UConn Physics department took part in the 51’st annual ascent up Mount Monadnock, near Jaffrey, New Hampshire. After the hike, the then-hungry hikers descended to the campground near Gilson Pond and enjoyed some well-earned refreshments.
The University of Connecticut, Department of Physics, is proud to announce that on October 20, 2023, Gérard Mourou, professor and member of Haut Collège at the École Polytechnique and A. D. Moore Distinguished University Professor Emeritus at the University of Michigan and 2018 Nobel Prize winner, will be presenting the 25th Distinguished Katzenstein Lecture.
About 20% of UConn students are supported by the Center for Students with Disabilities. The true percentage of students who need help is even higher. With so many students who require diverse ways of learning, how can faculty make sure their teaching is adequate, effective and inclusive for all students? In order to address this […]
Dear Friends of UConn Physics, Before highlighting some of the major events in the Physics Department during the past year, I need to sincerely thank Prof. Barry Wells for his leadership as Department Head for the past five years. Dr. Wells guided the department through the turbulent times of the COVID pandemic and resulting shutdown […]
Mirion Technologies, Inc. (https://www.mirion.com) formerly Canberra Inc., located in Meriden, CT, a worldwide leading company for manufacturing of electronics and nuclear detectors, established a partnership with our Physics department. In this partnership between our Physics department and a local industry, our students are encouraged to apply to spend a summer internship in the “real world” […]
Graduate student Debadarshini Mishra, Department of Physics, University of Connecticut
Photo-Induced Ultrafast Dynamics in Molecules
Imaging electronic and molecular dynamics at ultrafast timescales is crucial for understanding the mechanisms of chemical reactions, which are of fundamental importance in fields ranging from materials science to biochemistry. Furthermore, gaining insights into these processes at the atomic and molecular levels can enable precise control over reaction dynamics, leading to significant technological advancements through the development of efficient catalysts, innovative materials, and targeted drugs. In this dissertation talk, I will present my work on imaging time-resolved dynamics in molecular systems, using various light sources and ultrafast spectroscopy techniques. First, I will discuss a method for the direct visualization of neutral fragments in roaming reactions, which involve an unconventional dissociation process, using coincident Coulomb explosion imaging. Next, I will explore ultrafast electron diffraction as a different yet complementary imaging technique to identify the competing non-radiative relaxation pathways for a UV-excited molecule. Finally, I will briefly discuss our recent work on relaxation and fragmentation dynamics in large molecules, particularly C60, and isomerization and excited-state dynamics in small molecules.
Graduate student Mitchell Bredice, Department of Physics, University of Connecticut
Kinetics, Nucleation, and Relaxation Dynamics of Ion-Seeded Nanoparticles
The recent interest in studying the adsorption and emission spectra of the hazy atmospheres of exoplanets stimulates the interest in clusters, small aggregates of atoms or molecules. The nucleation and dynamics of nanoparticles in the Earth’s atmosphere and their impact on the global climate and environment is another important area of research stimulating investigations of nucleation processes. However, how these small aggregates form is not wholly understood. Traditionally, nucleation of clusters or other phases is described through Classical Nucleation Theory. Although this theory has many discrepancies in describing the nucleation of submicron particles. In this work, we have performed molecular dynamics simulations of the nucleation of ion-seeded nanoparticles, specifically ArnH+ clusters, to investigate the microscopic mechanisms of nucleation from a gas or liquid phase. From these simulations, we have studied the stages of the nonequilibrium and equilibrium growth of ArnH+ clusters and analyzed the size distribution and internal energy relaxation of nascent clusters during different stages of their growth. The fundamental impact of the internal energy relaxation on the nonequilibrium nucleation of small ArnH+ clusters has been demonstrated. This analysis has generally been avoided in previous investigations due to assumptions of the equilibrium nature of the nucleation process. The results of our simulations showed that nanoparticles are formed in highly excited states, thus the cluster growth and relaxation are concurrent processes, and that relaxation of the cluster internal energy can delay cluster growth processes. To further investigate the internal energy relaxation, an ensemble of molecular dynamics simulations was performed for the detailed analysis of the average time evolution of kinetic, potential, and total energies of small ArnH+ clusters, and their kinetic energy relaxation. The results of the performed simulations have been explained through the use of a collisional Boltzmann equation describing the energy relaxation processes. Lastly, the general relationship between nonequilibrium growth and internal energy relaxation is discussed.
Graduate student Dharma Basaula, Department of Physics, University of Connecticut
This dissertation is focused on formulating, testing and validating a finite element method based computational framework for the evaluation and prediction of thermoelectric properties and performance of polycrystalline nanostructured materials and composites at mesoscale. The developed framework includes capabilities for building geometrical models of complex interfacial structures and, with the availability of appropriate input parameters, can be used predictively, providing new avenues for improvement of operational efficiency of nanoengineered thermo- electric materials and composites. The following benchmark problems were investigated on the first stage of this project, progressing from simple to more advanced cases: (a) effective Seebeck effect in a thermocouple; (b) Peltier heating and cooling at a single interface between two materials with different Seebeck coefficients; (c) coupled heat and electrical current transport through an anisotropic polycrystalline material. Excellent agreement with prior experimental or computational results was observed for the cases where such information was available. On the second stage, ‘digital twins’ for the experimental measurements of thermal and electrical conductivities, and Seebeck coefficient in a material sample were developed within the same computational framework, allowing one to evaluate its thermoelectric figure of merit ZT(T). This approach was tested on three popular nanocrystalline thermoelectric systems: n-type Si, n-type Si0.80Ge0.20, and p-type BiSbTe, providing excellent agreement with previously measured values of ZT(T) and highlighting the importance of interfacial properties for making accurate predictions of the material thermoelectric performance and efficiency. Finally, on the third stage, the sensitivity of sample thermoelectric properties and the resulting ZT(T) to variations in the system microstructure, morphology and input material parameters was elucidated.
Graduate student Bochao Xu, DEpartment of Physics, University of Connecticut
Scanning SQUID Investigation of Time-reversal Symmetry Breaking in Exotic Quantum Materials
Spontaneous breaking of time-reversal symmetry in condensed matter systems arises from correlated electronic arrangements leading to various quantum phenomena, such as ferromagnetism, unconventional superconductivity, and topological states of matter. However, these underlying electronic orders are often difficult to detect experimentally if the magnetism associated with the time reversal symmetry breaking is weak. In such cases, the subtle magnetization and complex domain structure call for investigation by experimental techniques with both high magnetic sensitivity and high spatial resolution. In this dissertation talk, I will discuss my exploration of time-reversal symmetry breaking in two systems: a magnetic Weyl semimetal and a Kagome material detected using scanning superconducting quantum interference device (SQUID) microscopy. Both materials exhibit intriguing magnetic structures which were not detectable by the bulk measurements. We show that the Weyl semimetal hosts a tunable heterogeneous domain structure that is likely linked to its unconventional electronic properties. Additionally, our local probe reveals a ferromagnetic-like state in the Kagome material system, contributing evidence to the highly controversial problem within the community regarding the existence of time-reversal symmetry breaking and its underlying mechanism in this material. These results highlight the significance of quantum sensing in advancing the frontier of new correlated materials, and showcase these materials as an ideal playground for studying the magnetism-electrons interplay.