Premium
Raman scattering from phonons and electronic excitations in UO 2 with different oxygen isotopes
Author(s) -
Lv Junbo,
Li Gan,
Guo Shulan,
Shi Yan
Publication year - 2016
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4785
Subject(s) - phonon , raman spectroscopy , raman scattering , oxygen , stoichiometry , isotope , isotopes of oxygen , oxide , uranium , analytical chemistry (journal) , chemistry , atomic physics , materials science , condensed matter physics , physics , optics , nuclear chemistry , nuclear physics , organic chemistry , chromatography , metallurgy
Comparison of the phonons and electronic excitations of UO 2 with different oxygen isotopes ( 16 O, 18 O), two purely electronic excitations at 4162 and 5778 cm −1 have been evidenced by their limited shift, when 16 O is replaced by 18 O. The bands observed at 570, 1144 and 2300 cm −1 in U 16 O 2 shift to 545, 1091 and 2190 cm −1 for U 18 O 2 . The wavenumbers and the isotope shifts of these bands exhibit multiple relationships. It supports the assignments of the 1LO (~570 cm −1 ) and 2LO (~1144 cm −1 ) phonons for U 16 O 2 . Both bands exhibit marked decrease for increasing O/U ratio. The observed phenomenon is regarded as a good estimation of the stoichiometry of a uranium oxide. In addition, by analyzing the intensity ratios of the 2LO to 1LO phonons for various UO 2 samples, the 2LO band is assigned to the Fröhlich interaction. Defect‐induced and/or deformation potential mechanisms play a dominant role for the 1LO band. Copyright © 2015 John Wiley & Sons, Ltd.