Computational studies of nano-scaled materials and clusters

Revolutionized by the constant growth of computer power, quantum chemistry has become a widely used tool to offer new insights on the behavior of materials and clusters at the nano-scale, which complements our traditional way of doing science. In this dissertation, nano-materials functionalization (boron nitride nanotubes, two-dimensional hexagonal boron-nitride oxide) are investigated theoretically by using density functional theory in Chapter 2 and Chapter 3, including both geometric and electronic properties. In Chaper4, a benchmark study of performance of different density functional for small gold clusters and their oxides is discussed. We conclude that the hybrid functionals (HSE06, PBE0, and B3LYP) and the M06 functional with large basis sets can give reasonable O-O bond length and adsorption energy of O2. The GGA functionals (PBE and TPSS) tend to overestimate the adsorption energy and O-O bond length. At last, Born-Oppenheimer molecular dynamics (BOMD) simulation are applied to explore the dynamic properties of halide anion in the nano-scaled water droplet in Chapter 5. It shows that contrary to behavior of other halide anions, Cl- in the water droplet appears to exhibit no strong tendency of surface or bulk preference at either the supercooled or ambient condition, a phenomenon not previously reported in the literature..