content_image/361448.jpg content_image/361452.jpg
is obtained from, 

<img src='content_image/361448.jpg'>

<img src='content_image/361452.jpg'>

where the position of the n th oxygen atom within the unit cell is given by ( u , v , w ), and f$_{O}$ 2 − is the O 2 − form factor [27]. The La and Ni atoms are assumed to reside on the ideal corner and body-centered positions, respectively, and thus we do not consider a rhombohedral distortion of the La positions. Given this assumption, only the oxygen atoms contribute to the half-order peak intensities. We account for the octahedral rotations by doubling the 

