Overview

The goal of our research program is to investigate fundamental interactions between photons and molecular systems to advance our quantitative understanding of electron correlations, charge transfer and many body phenomena.

Nora Berrah
Nora Berrah

Our research investigations focus on probing on femtosecond time-scale multi-electron interactions and tracing nuclear motion in order to understand and ultimately control energy and charge transfer processes from electromagnetic radiation to matter. Most of our work is carried out in a strong partnership with theorists.

  • In our research program, we use the brightness, spectral resolution, tunability and polarization of the Advanced Light Source (ALS) synchrotron radiation facility, at the Lawrence Berkeley National Laboratory, to study with unprecedented level of detail, multi-electron excitation via inner-shell photoionization. We combine this state of the art source with high-resolution differential detection techniques, including imaging methods, for the characterization and visualization of structures and properties, to probe the many-body problem from the atomic to the nanoscale system.
  • These past 5 years, we have included in our research program investigation of non-linear physics, quantum control of atoms, molecules, and clusters with emphasis on short wavelength radiation, ultrafast time scales and strong laser fields. This research involves the use of intense femtosecond free electron lasers (FEL) in the vuv and x-ray regimes to probe physical and chemical processes that happen on ultrafast time scales. We use vuv photons from the FLASH FEL in Germany, FERMI@Elettra in Italy and x-rays from the XFEL at SLAC, Stanford, CA.
  • We are building a laser lab at UConn physics department that incorporates a femtosecond laser and VMI spectrometers to investigate molecular dynamics at the fs time scale in small and large systems, such as bio-molecules.

We have several experimental apparatus which we use at the ALS, LCLS and some under construction at UConn:

  • A velocity map imaging spectrometer (VMI) to measure e-ions as well as ion-ion coincidences at UConn and ALS.
  • 2 long (647mm) TOF analyzers positioned 125.3° apart, in a rotatable chamber, allowing simultaneous measurements to be made at, for eg., 54.7° (magic angle) and 0° with respect to the polarization vector of the incident radiation at ALS
  • A rotatable Scienta (SES-200) hemispherical analyzer capable of collecting very high resolution photoelectron spectra (PES) at selected photon energies over a wide range of electron kinetic energies at ALS
  • A movable ion-photon beamline to study both positive and negative ion at ALS.
  • An x-ray split and delay which allows for x-ray pump-x-ray probe research at LCLS
  • A LAMP-Imaging instrument which consists of two pn-CCD imaging detector to study scattering from extended systems at LCLS
  • A LAMP-VMI spectrometers to measure dynamics in atoms, molecules and extended systems at LCLS