Compton profiles and electronic structure of HgBr(2) and HgI(2)

Area of Science:

• Solid-state physics and chemistry
• Materials science
• Quantum chemistry

Background:

• Compton scattering provides insights into electron momentum distributions in solids.
• Mercury halides (HgBr2, HgI2) are compounds with interesting electronic and optical properties.
• Theoretical calculations are crucial for interpreting experimental data and understanding material behavior.

Purpose of the Study:

• To experimentally determine the Compton line shapes of HgBr2 and HgI2 for the first time.
• To theoretically compute Compton profiles and compare them with experimental data.
• To investigate the electronic structure, including energy bands and density of states, of these mercury halides.

Main Methods:

• Experimental measurement of Compton line shapes using a (137)Cs Compton spectrometer.
• Theoretical computation of Compton profiles via Hartree-Fock (HF) and density functional theory (DFT) using the linear combination of atomic orbitals (LCAO) method.
• Calculation of energy bands and density of states (DOS) using LCAO and full potential linearized augmented plane wave (FP-LAPW) methods.

Main Results:

• Experimental Compton line shapes for HgBr2 and HgI2 were successfully obtained.
• Theoretical Compton profiles from HF and DFT methods were computed for comparison.
• Analysis of equal-valence-electron-density profiles suggests HgI2 exhibits higher covalency than HgBr2, consistent with valence charge density calculations.
• Experimental isotropic profiles showed better agreement with HF data.
• Photoluminescence and detection properties of both halides were discussed.

Conclusions:

• The study provides the first experimental validation of Compton profiles for HgBr2 and HgI2.
• Hartree-Fock calculations offer a better description of the experimental Compton profiles compared to DFT in this context.
• The findings contribute to a deeper understanding of the electronic structure and bonding characteristics of mercury halides.