Ab initio study electronic structures of LiYF4 crystal containing interstitial oxygen atoms

The positions of the interstitial oxygen atoms in LiYF4 crystal are simulated by computer technologies. It is found that the total energy of cluster is low when interstitial oxygen atoms exist around the Li+ ion. Basing on the computer results, the electronic structures of perfect LiYF4 and the LiYF4 containing interstitial oxygen atoms with the lattice structure optimized are studied within the framework of the density functional theory. By analyzing the calculated results it can be concluded that an interstitial oxygen atom could combine with formal lattice fluorine ions forming molecular ions, which cause the 260 nm absorption band.