**3.6 Raman spectroscopy**

*Rare Earth Elements and Their Minerals*

**Figure 5.**

**82**

**Figure 6.**

tion of the clustered particles [1, 2].

**3.5 X-ray photoelectron spectroscopy (XPS)**

*EDX spectra of Gd2O3 phosphor: (A) glycerin fuel and (B) urea fuel.*

EDX mapping measurements were carried Gd2O3 powders to analyze the composi-

*Transmission electron microscope image of Gd2O3 phosphor: (A) glycerin fuel and (B) urea fuel.*

XPS is a surface compositional investigation system that can be utilized to examine the surface chemistry of a material in its as-formed state, or after some treatment, for instance: cracking, cutting, or scratching in air or UHV to uncover the bulk chemistry, ion beam etching to wipe off a few or the majority of the surface

To understand the molecular structure, Raman effect has been used, and the obtained Raman data can be compared with the infrared spectra. Raman spectroscopy is very informative to illustrate the structure of the phosphor. It is a nondestructive device to investigate vibrational, rotational, and other low recurrence modes in the frameworks under study. **Figure 8** demonstrates the Raman spectra of Gd2O3 obtained by combustion synthesis method. The spectra were recorded at room temperature with an excitation wavelength of 633 nm He-Cd laser. An broad and intense Raman crest at 340 cm<sup>−</sup><sup>1</sup> along with less extreme peaks was seen at 375, 395, 424, and 451 cm<sup>−</sup><sup>1</sup> . The outcomes are in great concurrence with the recently distributed Raman spectroscopic examinations on Gd2O3 nanoparticles [1].
