OH-1 absorption bands of LiNbO3 with varying composition

This paper reports that OHabsorption bands of lithium niobate crystal have been measured at room temperature, and the band shape depending on the crystal composition has been observed. The OHabsorption bands are fitted with three Lorentzian peaks by varying position, halfwidth, and height. Nearly constant peak positions (3468, 3481 and 3490 cm-1) are obtained for all samples. It shows that the height and area of the decomposed peaks vary with the Li composition in a complex way. However, the combinations of these fitting parameters show a linear dependence on the composition up to nearly 50 mol%, which is very useful for the composition determination in a wide range. The linear relationships between the parameter combinations and Li composition are also presented quantitatively. In addition, the explanations were given for the excellent composition linearity of parameter combinations.