Ab Initio Study of Electronic and optical properties of cesium Chloride

Abstract

In this research, we conducted a theoretical study of CsCl using first-principles calculations based on density functional theory (DFT) within the local density approximation (LDA) implemented via siesta software package. calculations included electronic and optical properties of this compound and compare the outcomes with prior literature. The numerical outcomes demonstrate a wide band gap of 5.0357eV, with the valence band maximum (VBM) and conduction band minimum (CBM) pinned at -3.0408eV and 1.9946eV. Regarding the evaluation of the optical properties derived from the dielectric function, it shows that the absorption coefficient remains negligible below the gap before surging sharply in the ultraviolet (UV) domain, reaching peak value of nearly 2x106cm-1. This surge aligns with maximum reflectivity of approximately 0.7 at a plasmon resonance energy of around 16. 5eV.these insights confirm that CsCl combines excellent visible -to -inferred transparency with a robust UV photonic responsiveness, establishing suitability for advanced optical windows and spectral filter applications.