RUI: theory of time delays in molecular photoionization and photodetachment

The National Science Foundation Division of Physics awarded California State University, Maritime Academy $218,614 on September 1, 2026, under the Mathematical and Physical Sciences program (CFDA 47.049) to develop theoretical methods for attosecond time delays in molecular photoionization and photodetachment.

The recipient will apply ab initio electron-molecule scattering methods—including Complex Kohn, Schwinger Variational, and R-matrix approaches—to quantify near-threshold photoemission time delays in molecular systems, including angular dependence and resonance effects. The work addresses open questions in ultrafast atomic, molecular, and optical physics: threshold behaviors of attosecond time delays in photodetachment, interpretation of delays without long-range Coulomb effects, and identification of molecular systems with the strongest electron correlation, polarization, or resonance signatures. The project will generate predictions comparable to existing calculations and attosecond streaking techniques, support planned measurements at research institutions, and lay groundwork for the first measurements of photodetachment time delays in molecular anions. Undergraduate researchers will participate in modeling, analysis, and interpretation of molecular time delays.

The award supports work at California State University, Maritime Academy in Vallejo, California, with a period of performance from September 1, 2026, through August 31, 2029. This is a Research in Undergraduate Institutions (RUI) project grant.

Abstract

This project is focused on the theory of attosecond time delays in molecular photoionization and photodetachment. The work will generate predictions directly comparable to existing calculations and attosecond streaking techniques and interpret planned measurements at research institutions while training undergraduate researchers. This project will advance our theoretical understanding of how correlation, exchange, and polarization potentials influence photoemission in molecular systems, and will develop new theoretical frameworks that bridge these insights with experimental measurements. This effort will involve undergraduate students who will participate in the modeling, analysis, and interpretation of molecular time delays. This work will directly support ongoing experiments, laying the groundwork for the first measurements of photodetachment time delays in molecular anions. The PI will develop and apply AB initio electron-molecule scattering methods (complex kohn, schwinger variational, and r-matrix) to quantify near-threshold photoemission time delays, including angular dependence and resonance effects. This research addresses several open and compelling questions at the frontier of ultrafast AMO physics: what are the threshold behaviors of attosecond time delays in photodetachment? Can we interpret such delays without long-range coulomb effects? Which molecular systems reveal the strongest electron correlation, polarization, or resonance features in time delay signatures? The scientific merit lies in (1) developing rigorous theoretical methods for time-resolved molecular dynamics, (2) predicting signatures of fundamental interactions (e.g., dipole and polarization effects) in measurable quantities, and (3) expanding attosecond science into new territory?molecular photodetachment?where no experimental measurements yet exist. This work aligns closely with NSF's goals in theoretical AMO physics and will contribute foundational insights to the field. 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.- subawards are not planned for this award.