Related Experiment Video
Updated: Jun 1, 2025

Picometer-Precision Atomic Position Tracking through Electron Microscopy
Published on: July 3, 2021
Investigation into the vibrational characteristics of monolayered ruddlesden-popper compounds (Sr, Ba)2HfO4
Neenu Saini1, Ruby Jindal2, Archana Tripathi3
1Department of Physics, School of Basic and Applied Sciences, K.R. Mangalam University, Gurugram, Haryana 122103, India; Department of Physics, Pt. Jawaharlal Nehru Govt. College, Faridabad, Haryana 121002, India.
Abstract:
The analysis of Raman and Infrared (IR) phonons in monolayered tetragonal (Sr, Ba)2HfO4 compounds, which exhibit D174h symmetry and belong to the I4/mmm phase of space group 139 with Z = 2, has been conducted using normal coordinates. The Sr2HfO4 and Ba2HfO4 compounds are the first members of the Ruddlesden-Popper (RP) series denoted as (Sr, Ba)n+1HfO3n+1 with n = 1. Nine Short-Range Force Constants (SRFC) have been included in theoretical calculations to analyze the optical phonons of Sr2HfO4 and Ba2HfO4 compounds within the I4/mmm phase. The assignments of optical vibrational modes in (Sr, Ba)2HfO4 compounds have been determined using Wilson's GF-Matrix Method and cross-referenced with data obtained from compounds sharing similar structural characteristics. The analysis also involved studying how the exchange of cation-A (A = Sr, Ba) impacts the lattice dynamics of the isostructural compounds A2HfO4 (A = Sr, Ba) in monolayered tetragonal structures. In this analysis, a comparison has been made between the vibrational modes at the Zone Center, the force constants, and bond lengths to assess the influence of the cation exchange. Furthermore, for each normal mode in the Ruddlesden-Popper phase (Sr, Ba)2HfO4, the examination of Potential Energy Distribution (PED) sheds light on the significant impact exerted by Short-Range Force Constants on the calculated vibrational modes, providing a deeper understanding of their behavior and interactions.
Related Concept Videos
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
UV–Vis Spectroscopy: Molecular Electronic Transitions
UV–Vis Spectroscopy: Woodward–Fieser Rules
IR Spectroscopy: Molecular Vibration Overview
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to...

