Sammenlign metoder

	Konfigurationsinteraktion	EXAFS	XANES
Fagområde	Spektroskopi	Spektroskopi	Spektroskopi
Familie	Process / pipeline	Process / pipeline	Process / pipeline
Oprindelsesår	1960	1971	1975
Ophavsperson	Clemens Roothaan	Edward Stern	Peter Lee
Type	Computational method	Synchrotron technique	Synchrotron technique
Oprindelig kilde	Roothaan, C. C. J. (1960). New developments in molecular orbital theory. Reviews of Modern Physics, 32(2), 179-185.	Sayers, D. E., Stern, E. A., & Lytle, F. W. (1971). New technique for investigating noncrystalline structures: Fourier analysis of the extended X-ray absorption fine structure. Physical Review Letters, 27(18), 1204-1207.	Lee, P. A., & Pendry, J. B. (1975). Theory of extended x-ray absorption fine structure. Physical Review B, 11(8), 2795-2811.
Aliasser	CI, configuration interaction method, CI calculations	EXAFS spectroscopy, X-ray absorption spectroscopy	XANES spectroscopy, near-edge X-ray absorption
Relaterede	3	3	3
Resumé	Configuration Interaction (CI) is a post-Hartree-Fock quantum chemistry method that improves upon mean-field molecular orbital theory by treating electron correlation through a linear combination of electronic configurations. Introduced by Roothaan in 1960, CI corrects for the fundamental limitation of single-determinant theory by allowing the wavefunction to be a superposition of excited-state Slater determinants, systematically accounting for electron-electron interactions.	Extended X-ray Absorption Fine Structure (EXAFS) is a synchrotron-based X-ray spectroscopy technique that measures the local geometric and electronic structure around a specific atom in any material, crystal or amorphous. Discovered by Sayers, Stern, and Lytle in 1971, EXAFS reveals interatomic distances, coordination numbers, and disorder in the atomic environment by analyzing oscillations in the X-ray absorption spectrum above an absorption edge.	X-ray Absorption Near Edge Structure (XANES) is a synchrotron X-ray spectroscopy technique that measures the electronic and geometric structure around a specific atom by analyzing the X-ray absorption spectrum within about 50 eV of an absorption edge. Developed by Lee and Pendry in 1975, XANES is complementary to EXAFS and reveals valence state, local symmetry, and unoccupied orbital structure through near-threshold features and resonances.