Q-Chem Webinar 48

The ezSpectra Suite: An easy-to-use Toolkit for Spectroscopy Modeling

Dr. Samer Gozem
Presented by Dr. Samer Gozem on

Samer Gozem is an Assistant Professor of Chemistry at Georgia State University. He completed his B.S. in Chemistry in 2008 at the American University of Beirut in Lebanon and his Ph.D. in Photochemical Sciences in 2013 at Bowling Green State University, where we worked with Prof. Massimo Olivucci on modeling biological photoreceptors with hybrid quantum mechanical/molecular mechanical methods. Samer then carried out his postdoctoral training at the University of Southern California with Prof. Anna Krylov, where he worked on modeling photoionization and photodetachment processes. He joined the faculty at Georgia State University in 2017. His interests include using both classical and quantum mechanics to study light-responsive chemical and biological systems.


A molecule’s spectrum is a unique fingerprint that identifies it and characterizes its molecular and electronic structure. Electronic structure calculations provide key parameters for interpreting these spectra. However, modeling of spectra rarely ends at the electronic structure calculations; it often requires additional steps, which entail combined treatments of electronic and nuclear degrees of freedom and accounting for specifics of the experimental setup (light energy, polarization, averaging over molecular orientations, etc.).

In this webinar, we will introduce ezFCF (formerly ezSpectrum) and ezDyson. Both codes can be downloaded from http://iopenshell.usc.edu/downloads​. ezFCF calculates stick excitation or photoelectron/photodetachment spectra for polyatomic molecules within the double–harmonic approximation. ezDyson calculates absolute photodetachment/ photoionization cross-sections, photoelectron angular distributions (PADs), and anisotropy parameters (beta) using Dyson orbitals computed by an ab initio program. The webinar will cover how to use these programs with Q-Chem to simulate UV/vis absorption spectra, photoionization spectra, and photoelectron anisotropies.

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