Bayesian inferencing and deterministic anisotropy for molecular geometry retrieval in gas phase diffraction experiments

Mar 13, 2023, 3:55 PM
Bldg 53 / Room 1320 - Panofsky Auditorium (SLAC)

Bldg 53 / Room 1320 - Panofsky Auditorium


2575 Sand Hill Rd Menlo Park, CA USA
Oral Methods Methods


Kareem Hegazy (STANFORD U., PHYS. DEPT.)


Ultrafast molecular gas phase diffraction is a vital tool for retrieving time dependent molecular structures. We are limited in the systems we can study as we generally require complex molecular dynamics simulations to interpret the results. We develop an alternative analysis to approximate the molecular geometry distribution $|\Psi(\mathbf{r}, t)|^2$ that does not require such complex simulations. We achieve real-space resolutions of 1 pm to 10 fm while uniquely defining the molecular structure. We demonstrate our method's viability by retrieving the ground state geometry distribution $|\Psi(\mathbf{r})|^2$ for simulated stretched NO$_2$ and measured N$_2$O. Our method expands the capabilities of ultrafast molecular gas phase diffraction to measure other variables, like the width of $|\Psi(\mathbf{r}, t)|^2$. By not relying on complex simulations and with the order 100 fm resolution, our method has the potential to effectively turn ultrafast molecular gas phase diffraction into a discovery oriented technique, exploring systems that are prohibitively difficult to simulate.

UED is supported in part by DOE BES Scientific User Facilities Division and SLAC UED/UEM program development: DE-AC02-05CH11231.

This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.

Primary authors

Kareem Hegazy (STANFORD U., PHYS. DEPT.) Prof. Varun Makhija (Department of Chemistry and Physics, University of Mary Washington) Dr Ryan Coffee (Stanford PULSE Institute, SLAC National Accelerator Laboratory)


Prof. Phil Bucksbaum (Department of Physics and Applied Physics, Stanford University) Dr Jeff Corbett (SLAC National Accelerator Laboratory) James Cryan (SLAC) Prof. Markus Guehr (Institut fur Physik and Astronomie, Universitat Potsdam) Dr Nick Hartmann (Linac Coherent Light Source) Dr Markus Ilchen (European XFEL) Keith Jobe (SLAC) Prof. Renkai Li (Department of Engineering Physics, Tsinghua University) Dr Igor Makasyuk (SLAC National Accelerator Laboratory) Dr Xiaozhe Shen (SLAC National Accelerator Laboratory) Dr Xijie Wang (SLAC National Accelerator Laboratory) Dr Stephen Weathersby (SLAC National Accelerator Laboratory) Prof. Jie Yang (Department of Engineering Physics, Tsinghua University)

Presentation materials