Finite temperature effects on the X-ray absorption spectra of lithium compounds: First-principles interpretation of X-ray Raman measurements

Journal Article · Tue Jan 21 00:00:00 EST 2014 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4856835· OSTI ID:22255278

Pascal, Tod A.; Prendergast, David ^[1]; Boesenberg, Ulrike; Kostecki, Robert; Richardson, Thomas J. ^[2]; Weng, Tsu-Chien; Sokaras, Dimosthenis; Nordlund, Dennis ^[3]; McDermott, Eamon; Moewes, Alexander ^[4]; Cabana, Jordi ^[2]

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1. The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, California 94720 (United States)
2. Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States)
3. Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford, California 94720 (United States)
4. University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, Saskatchewan S7N 5E2 (Canada)

We elucidate the role of room-temperature-induced instantaneous structural distortions in the Li K-edge X-ray absorption spectra (XAS) of crystalline LiF, Li{sub 2}SO{sub 4}, Li{sub 2}O, Li{sub 3}N, and Li{sub 2}CO{sub 3} using high resolution X-ray Raman spectroscopy (XRS) measurements and first-principles density functional theory calculations within the eXcited electron and Core Hole approach. Based on thermodynamic sampling via ab initio molecular dynamics simulations, we find calculated XAS in much better agreement with experiment than those computed using the rigid crystal structure alone. We show that local instantaneous distortion of the atomic lattice perturbs the symmetry of the Li 1s core-excited-state electronic structure, broadening spectral line-shapes and, in some cases, producing additional spectral features. The excellent agreement with high-resolution XRS measurements validates the accuracy of our first-principles approach to simulating XAS, and provides both accurate benchmarks for model compounds and a predictive theoretical capability for identification and characterization of multi-component systems, such as lithium-ion batteries, under working conditions.

• OSTI ID: 22255278
• Journal Information: Journal of Chemical Physics, Vol. 140, Issue 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
ACCURACY
CRYSTAL STRUCTURE
DENSITY FUNCTIONAL METHOD
ELECTRIC BATTERIES
ELECTRONIC STRUCTURE
EXCITED STATES
LITHIUM CARBONATES
LITHIUM FLUORIDES
LITHIUM IONS
LITHIUM NITRIDES
LITHIUM OXIDES
LITHIUM SULFATES
MOLECULAR DYNAMICS METHOD
RAMAN SPECTROSCOPY
SIMULATION
TEMPERATURE DEPENDENCE
X RADIATION
X-RAY SPECTRA
X-RAY SPECTROSCOPY