Computational insights into structural and optical properties of P-containing and N-containing ligands capped CdSe clusters

The ligand effects on the structures and properties (energetics, binding energies, charge distribution and optical properties) of the (CdSe)_n clusters (n = 3, 6, and 10) with P-containing (PH₃, PH₂Me, PHMe₂ and PMe₃) and N-containing (NH₃, NH₂Me, NHMe₂ and NMe₃) have been studied using density functional theory. The P atom and N atom in the ligands interact with Cd and form Cd–P and Cd–N bonds. The influence of P-containing ligands can be enhanced with increasing CH₃ of ligands, while the N-containing ligands influence slightly change. A blueshift in absorption band was predicted for the clusters with increasing CH₃ of P-containing ligands. We also found that the calculated binding energies for various ligands are found to decrease in the order PMe₃ > NH₂Me > NHMe₂ > NH₃ > NMe₃ > PHMe₂ > PH₂Me > PH₃. The use of hydrogen atom for modelling of the CdSe cluster passivating ligands is found to yield unphysical results as well.