Study of Optical Phonons of Monolayered Ruddlesden-Popper Compounds A2ZrO4 (A = Sr, Ba)

• Published in: Journal of inorganic and organometallic polymers and materials 2024-03, Vol.34 (3), p.1301-1308
• Main Authors: Saini, Neenu, Jindal, Ruby, Tripathi, Archana, Garg, Alka
• Format: Article
• Language: English
• Subjects: Barium; Chemistry; Chemistry and Materials Science; Energy distribution; Infrared analysis; Inorganic Chemistry; Lattice vibration; Mathematical analysis; Matrix methods; Organic Chemistry; Phonons; Polymer Sciences; Potential energy; Strontium; Vibration mode
• ISSN: 1574-1443; 1574-1451
• DOI: 10.1007/s10904-023-02892-6

The monolayered tetragonal (Sr, Ba) 2 ZrO 4 compounds, characterized by symmetry and phase I4/mmm (Z = 2), have undergone analysis to determine the Raman and Infrared (IR) phonons using normal coordinates. These compounds, namely Sr 2 ZrO 4 and Ba 2 ZrO 4 , represent the initial members of the (Sr, Ba) n+1 ZrO 3n + 1 Ruddlesden-Popper (RP) series with n = 1. Theoretical calculations have been performed for the optical phonons of the Sr 2 ZrO 4 and Ba 2 ZrO 4 compounds in phase I4/mmm, incorporating nine Short-Range Force Constants (SRFC) for the first time. Assignments of the optical vibrational modes for the (Sr, Ba) 2 ZrO 4 compounds were established by comparing them with available data from isostructural compounds, utilizing Wilson’s GF-Matrix Method. The analysis further encompassed investigating the effects of cation-A (A = Sr, Ba) exchange on the lattice dynamics of the monolayered tetragonal A 2 ZrO 4 (A = Sr, Ba) isostructural compounds. This analysis involved a comparison of Zone Centre vibrational modes, force constants, and bond lengths to evaluate the impact of the exchange. Additionally, for each normal mode in the Ruddlesden-Popper phase A 2 ZrO 4 (A = Sr, Ba), the Potential Energy Distribution (PED) was analyzed to elucidate the considerable influence of short-range force constants on the calculated phonons.