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Title: Ab Initio Computation of Rotationally-Averaged Pump–Probe X-ray and Electron Diffraction Signals

Journal Article · · Journal of Chemical Theory and Computation

We develop a new algorithm for the computation of the rotationally averaged elastic molecular diffraction signal for the cases of perpendicular or parallel pump–probe geometries. The algorithm first collocates the charge density from an arbitrary ab initio wave function onto a Becke quadrature grid [A. Becke, J. Chem. Phys. 1988, 88, 2457], providing a high-fidelity multiresolution representation of the charge density. A double sum is then performed over the Becke grid points, and the interaction between points computed using the scattering kernels of Williamson and Zewail [J. C. Williamson and A. H. Zewail, J. Phys. Chem. 1994, 98, 2766]. These kernels analytically average over the molecular orientations with the cos2γ selection factor appropriate for one-photon dipole absorption in a perpendicular pump–probe geometry. We demonstrate that the method is converged with small grids containing <500 points/atom. We implement the algorithm on a GPU for increased efficiency and emonstrate the algorithm for molecules with up to a few dozen atoms. We explore the accuracy of the independent atom model (IAM) by comparison with our new and more accurate method. We also investigate the possibility of detecting signatures of electronic transitions in polyatomic pump–probe diffraction experiments.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1527342
Journal Information:
Journal of Chemical Theory and Computation, Journal Name: Journal of Chemical Theory and Computation Journal Issue: 3 Vol. 15; ISSN 1549-9618
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

References (51)

Elements of Modern X-ray Physics book March 2011
Zerstreuung von Röntgenstrahlen journal January 1915
Ultrafast Electron Diffraction (UED): A New Development for the 4D Determination of Transient Molecular Structures journal June 2003
II. Diffraction Physics journal January 1977
SG-0: A small standard grid for DFT quadrature on large systems journal January 2006
Two-electron integral evaluation on the graphics processor unit journal January 2007
A standard grid for density functional calculations journal July 1993
Direct imaging of excited electronic states using diffraction techniques: theoretical considerations journal November 1996
VMD: Visual molecular dynamics journal February 1996
Comparison of ultrafast electron and X-ray diffraction – A computational study journal September 2017
Ultrafast X-ray Scattering from Molecules journal February 2016
Nonadiabatic Ab Initio Molecular Dynamics with the Floating Occupation Molecular Orbital-Complete Active Space Configuration Interaction Method journal December 2017
Dynamic Precision for Electron Repulsion Integral Evaluation on Graphical Processing Units (GPUs) journal March 2011
Ab Initio Calculation of Molecular Diffraction journal October 2014
Quantum Chemistry on Graphical Processing Units. 1. Strategies for Two-Electron Integral Evaluation journal January 2008
Quantum Chemistry on Graphical Processing Units. 2. Direct Self-Consistent-Field Implementation journal March 2009
Quantum Chemistry on Graphical Processing Units. 3. Analytical Energy Gradients, Geometry Optimization, and First Principles Molecular Dynamics journal August 2009
Ultrafast Electron Diffraction. 4. Molecular Structures and Coherent Dynamics journal March 1994
Ultrafast Diffraction Imaging of the Electrocyclic Ring-Opening Reaction of 1,3-Cyclohexadiene journal May 2001
Ab Initio Molecular Dynamics of Excited-State Intramolecular Proton Transfer Using Multireference Perturbation Theory journal November 2007
On the Theory of Time-Resolved X-ray Diffraction journal January 2008
Role of Rydberg States in the Photochemical Dynamics of Ethylene journal December 2011
Ultrafast X-ray and Electron Diffraction:  Theoretical Considerations journal November 1997
Ultrafast X-ray Diffraction Theory journal November 1998
Ab Initio Multiple Spawning:  Photochemistry from First Principles Quantum Molecular Dynamics journal June 2000
Direct observation of bond formation in solution with femtosecond X-ray scattering journal February 2015
Diffractive imaging of a rotational wavepacket in nitrogen molecules with femtosecond megaelectronvolt electron pulses journal April 2016
First lasing and operation of an ångstrom-wavelength free-electron laser journal August 2010
A compact X-ray free-electron laser emitting in the sub-ångström region journal June 2012
Imaging rotations and vibrations in polyatomic molecules with X-ray scattering journal January 2017
Ab initio calculation of inelastic scattering journal January 2017
Ab initio treatment of time-resolved x-ray scattering: Application to the photoisomerization of stilbene journal December 2006
Ab initio floating occupation molecular orbital-complete active space configuration interaction: An efficient approximation to CASSCF journal June 2010
A multicenter numerical integration scheme for polyatomic molecules journal February 1988
Molecular dynamics with electronic transitions journal July 1990
On-the-fly ab initio molecular dynamics with multiconfigurational Ehrenfest method journal December 2012
Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory journal July 2015
Elastic X-ray scattering from state-selected molecules journal October 2016
Analytic formulation of derivative coupling vectors for complete active space configuration interaction wavefunctions with floating occupation molecular orbitals journal November 2016
Communication: XFAIMS—eXternal Field Ab Initio Multiple Spawning for electron-nuclear dynamics triggered by short laser pulses journal November 2016
Monitoring nonadiabatic avoided crossing dynamics in molecules by ultrafast X-ray diffraction journal September 2017
Imaging electronic quantum motion with light journal July 2012
Ab initio multiple spawning dynamics of excited state intramolecular proton transfer: the role of spectroscopically dark states journal February 2008
Quantum dynamics simulations using Gaussian wavepackets: the vMCG method journal April 2015
Ultra-fast and ultra-intense x-ray sciences: first results from the Linac Coherent Light Source free-electron laser journal August 2013
Observation of femtosecond molecular dynamics via pump–probe gas phase x-ray scattering journal January 2016
Variational treatment of electron–polyatomic-molecule scattering calculations using adaptive overset grids journal November 2017
X-Ray Diffraction from Isolated and Strongly Aligned Gas-Phase Molecules with a Free-Electron Laser journal February 2014
Imaging Molecular Motion: Femtosecond X-Ray Scattering of an Electrocyclic Chemical Reaction journal June 2015
Self-Referenced Coherent Diffraction X-Ray Movie of Ångstrom- and Femtosecond-Scale Atomic Motion journal October 2016
Imaging CF 3 I conical intersection and photodissociation dynamics with ultrafast electron diffraction journal July 2018

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