Structures and Properties of(H_2GaN_3)_n(n=1-4)Clusters:A DFT Study

摘要

Computations on the systems of(H_2GaN_3)_n(n=1-4)are performed using the density functional theory(DFT)/B3LYP method with different basis sets.(H_2GaN_3)_2 possessing D_(2h),symmetry is found to exhibit the planar Ga_2N_2 ring structure.(H_2GaN_3)_3 involving a six-membered Ga_3N_3 ring is found to exhibit two minima with very similar binding energies(ca.-235 ~-231 kJ(center dot)mol~(-1)).One minimum is the newly found boat-like conformation possessing C_s symmetry.Another minimum possessing C_3v symmetry is the chair-like conformation.(H_2GaN_3)_4 occurs in several structures with Ga_4N_4 eight-membered ring structures that correspond to minima with slight energy differences among them.The structural changes of the clusters are large compared with the monomer.Frequency calculations are carried out on each optimized structure,and their infrared(IR)spectra are discussed.Thermodynamic properties demonstrate that the systems of H_2GaN_3 occur at dimer-trimer-tetramer equilibrium,and the trimer is the main component.