(Color online) Schematic illustration of PP-PTO (lead atoms, black solid circles).
(Color online) Experimental (a) and theoretical (b) Raman spectra of PP-PTO.
(Color online) Graphical representation of atomic displacements associated with the eigenvector corresponding to the Ag of 837 cm−1 (Fig. 3(A)), Bg of 227 cm−1 (Fig. 3(B)), Eg of 292 cm−1 (Fig. 3(C)) and Eg of 571 cm−1 (Fig. 3(D) modes). Lengths and angular deviations of the arrows are exaggerated for clarity, but the directions of the displacements are qualitatively correct. In Fig. 3(C) and Fig. 3(D), ⊗ and ⊙ represent the atomic displacements along the −c and +c axis, respectively, while ○ means no displacement.
Optimized structural parameters of PP-PTO compared with the experimental results.5
Selection rules for the Raman active modes for PP-PTO. “√” and “×” indicate visible and invisible, respectively.
Calculated and experimental frequencies (cm−1) and assignment of the Raman modes of PP-PTO. As a guide to the eye: the phonon frequency before the first horizontal line is not theoretically expected; the phonon frequencies after the second horizontal line are not observed in the experimental spectrum; other phonon frequencies are presented in increasing order.
Calculated frequencies (cm−1) and mode-effective charges of the IR TO and LO modes of PP-PTO.
Born effective charge and dielectric tensor elements of PP-PTO.
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