New coupled-cluster methods for linear and non-linear core-level spectroscopies in gas and condensed phases

University Of Southern California, Los Angeles CA

Investigators

Abstract

Professor Anna Krylov of the University of Southern California (USC) is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry. Chemists use light to look at molecules and materials. The use of light can help unravel how chemical reactions occur, the structure of molecules, and how these structures influence the properties of materials and biological molecules. Professor Krylov uses highly accurate theoretical tools to model what happens when molecules interact with very intense and high energy light. Her research has important applications in understanding photosynthesis and solar energy conversions, among other areas. This project includes training and mentoring graduate students and postdocs for careers in academia and industry. The project also makes contributions to the research infrastructure by integrating new computer codes into widely used programs (Q-CHEM and SPARTAN) and making them available to the broad chemistry community. The Q-CHEM software is given free of charge to major high-performance computing facilities in the U.S.A. and abroad. Professor Krylov is an active contributor to the Women in Science and Engineering program at USC. She maintains the "Women in Theoretical and Computational Chemistry, Material Science, and Biochemistry" webpage and Google group, promoting research by women. Krylov and her research group are extending highly reliable coupled-cluster and equation-of-motion coupled-cluster methods to the domain of core-level ionized and excited states by exploiting core-valence separation and damped response theory (or complex polarization propagator) approaches. They are developing theoretical framework and efficient computer codes for modeling XES (X-ray emission), RIXS (resonant inelastic X-ray scattering), X2PA (X-ray 2-photon absorption), and XSFG (X-ray sum-frequency generation) spectra. The new theoretical methods and software aid both fundamental and applied research using advanced light sources by allowing first-principles atomic-level modeling of optical properties such as X2PA, XSFG, and RIXS cross sections, XES spectra, and more. Professor Krylov is continuing her close collaborations with experimentalists to guide and calibrate theoretical developments, as well as help to design new experiments and interpret the experimental results. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.