TY - JOUR
T1 - Many-body effects in the X-ray absorption spectra of liquid water
AU - Tang, Fujie
AU - Li, Zhenglu
AU - Zhang, Chunyi
AU - Louie, Steven G.
AU - Car, Roberto
AU - Qiu, Diana Y.
AU - Wu, Xifan
N1 - Funding Information:
ACKNOWLEDGMENTS. This work was primarily supported by the Computational Chemical Center: Chemistry in Solution and at Interfaces funded by the US Department of Energy (DOE) under Award DE-SC0019394, as well as the Computational Materials Science Center: Center for Computational Study of Excited-State Phenomena in Energy Materials funded by the DOE under Contract DE-AC02-05CH11231. The work of F.T., C.Z., R.C., and X.W. on PI-DPMD simulation and XAS calculation was supported by the Computational Chemical Center: Chemistry in Solution and at Interfaces funded by the DOE under Award DE-SC0019394. The work of Z.L., S.G.L., and D.Y.Q. related to implementation of new methodology and algorithms to calculate XAS with the BerkeleyGW code was supported by the Center for Computational Study of Excited-State Phenomena in Energy Materials at the Lawrence Berkeley National Laboratory funded by the DOE under Contract DE-AC02-05CH11231, as part of the Computational Materials Sciences Program. The work of D.Y.Q. on the development of the Hilbert space downfolding approach for core-level spectroscopy was supported by the NSF under Grant DMR-2114081. The work by C.Z. on water structure by neural network potential was supported by the NSF through Award DMR-2053195. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the DOE, Office of Science under Contract DE-AC02-05CH11231. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the DOE under Contract DE-AC05-00OR22725. This research includes calculations carried out on high-performance computing (HPC) resources supported, in part, by the NSF through major research instrumentation Grant 1625061 and by the US Army Research Laboratory under Contract W911NF-16-2-0189.
Publisher Copyright:
Copyright © 2022 the Author(s).
PY - 2022/5/17
Y1 - 2022/5/17
N2 - X-ray absorption spectroscopy (XAS) is a powerful experimental technique to probe the local order in materials with core electron excitations. Experimental interpretation requires supporting theoretical calculations. For water, these calculations are very demanding and, to date, could only be done with major approximations that limited the accuracy of the calculated spectra. This prompted an intense debate on whether a substantial revision of the standard picture of tetrahedrally bonded water was necessary to improve the agreement of theory and experiment. Here, we report a first-principles calculation of the XAS of water that avoids the approximations of prior work, thanks to recent advances in electron excitation theory. The calculated XAS spectra, and their variation with changes of temperature and/or with isotope substitution, are in good quantitative agreement with experiments. The approach requires accurate quasiparticle wave functions beyond density functional theory approximations, accounts for the dynamics of quasiparticles, and includes dynamic screening as well as renormalization effects due to the continuum of valence-level excitations. The three features observed in the experimental spectra are unambiguously attributed to excitonic effects. The preedge feature is associated with a bound intramolecular exciton, the main-edge feature is associated with an exciton localized within the coordination shell of the excited molecule, and the postedge feature is delocalized over more distant neighbors, as expected for a resonant state. The three features probe the local order at short, intermediate, and longer range relative to the excited molecule. The calculated spectra are fully consistent with a standard tetrahedral picture of water.
AB - X-ray absorption spectroscopy (XAS) is a powerful experimental technique to probe the local order in materials with core electron excitations. Experimental interpretation requires supporting theoretical calculations. For water, these calculations are very demanding and, to date, could only be done with major approximations that limited the accuracy of the calculated spectra. This prompted an intense debate on whether a substantial revision of the standard picture of tetrahedrally bonded water was necessary to improve the agreement of theory and experiment. Here, we report a first-principles calculation of the XAS of water that avoids the approximations of prior work, thanks to recent advances in electron excitation theory. The calculated XAS spectra, and their variation with changes of temperature and/or with isotope substitution, are in good quantitative agreement with experiments. The approach requires accurate quasiparticle wave functions beyond density functional theory approximations, accounts for the dynamics of quasiparticles, and includes dynamic screening as well as renormalization effects due to the continuum of valence-level excitations. The three features observed in the experimental spectra are unambiguously attributed to excitonic effects. The preedge feature is associated with a bound intramolecular exciton, the main-edge feature is associated with an exciton localized within the coordination shell of the excited molecule, and the postedge feature is delocalized over more distant neighbors, as expected for a resonant state. The three features probe the local order at short, intermediate, and longer range relative to the excited molecule. The calculated spectra are fully consistent with a standard tetrahedral picture of water.
KW - X-ray spectroscopy
KW - liquid water
KW - many-body Green’s functions
KW - molecular simulation
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U2 - 10.1073/pnas.2201258119
DO - 10.1073/pnas.2201258119
M3 - Article
C2 - 35561212
AN - SCOPUS:85130008367
SN - 0027-8424
VL - 119
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 20
M1 - e2201258119
ER -