title: Near-edge x-ray absorption and natural circular dichroism spectra of L-alanine: a theoretical study based on the complex polarization propagator approach.
abstract: The complex polarization propagator method [J. Chem. Phys. 123, 194103 (2005)] has been employed in conjunction with density functional theory and gauge-including atomic orbitals in order to determine the near-edge x-ray absorption and natural circular dichroism spectra of L-alanine in its neutral and zwitterionic forms. Results are presented for the K-edges of carbon, nitrogen, and oxygen. In contrast to traditional methods, the proposed approach enables a direct determination of the spectra at an arbitrary frequency instead of focusing on the rotatory strengths for individual electronic transitions. The propagator includes a complete set of nonredundant electron-transfer operators and allows for full core-hole relaxation. The theoretical spectrum at the nitrogen K-edge of the zwitterion compares well with the experimental spectrum.
authors.affiliation: Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Auayporn
authors.initials: A
authors.lastname: Jiemchooroj
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekström
authors.forename: Patrick
authors.initials: P
authors.lastname: Norman
mesh_terms: D015502:Absorptiometry, Photon; D000409:Alanine / Q000737:chemistry*; D002942:Circular Dichroism; D007477:Ions; D008956:Models, Chemical; D011789:Quantum Theory
chemical_list: D007477:Ions; D000409:Alanine