The ozonization at the vacancy defect site of the single-walled carbon nanotube has been studied by static quantum mechanics and atom-centered density matrix propagation based ab initio molecular dynamics within a two-layered ONIOM approach. Among five different reaction pathways at the vacancy defect, the reaction involving the unsaturated active carbon atom is the most probable pathway, where ozone undergoes fast dissociation at the active carbon atom at 300 K. Complementary to the experiments, our work provides a microscopic understanding of the ozonization at the vacancy defect site of the single-walled carbon nanotube.

}, keywords = {AB-INITIO, DENSITY-MATRIX, ETHYLENE, FULLERENE, GAUSSIAN-ORBITALS, INITIO MOLECULAR-DYNAMICS, MECHANICS, OXYGEN, OZONE ADSORPTION, SIDEWALLS}, isbn = {1520-6106}, url = {The Staudinger reaction of phosphane and azide has been investigated by Atom-centered Density Matrix Propagation (ADMP) approach to ab initio molecular dynamics (AlMD) in combination with molecular orbital analysis within density functional theory. At room temperature, the reaction pathway with the cis initial attack dominates the Staudinger reaction. Electrostatic interaction, charge transfer, and covalent overlap are responsible for the initial attack and for the system to overcome the initial reaction barrier. The rotation Of PH3 and PH vibrations facilitate the isomerization of the system from cis intermediate to the last transition state, which indicates that small substituent groups on phosphane can facilitate the last stage of the Staudinger reaction. During the course of the reaction, the change of the average polarizability correlates positively to the change of the potential energy of the system, which clearly suggests that polar solvents can facilitate the overall reaction by stabilizing all transition states and reducing all reaction barriers.

}, keywords = {BORN-OPPENHEIMER DYNAMICS, CAR-PARRINELLO, DENSITY-FUNCTIONAL SCHEME, FORCE-FIELD, GAUSSIAN-ORBITALS, INITIO MOLECULAR-DYNAMICS, MATRIX, PATH, PHOSPHAZIDE, X-RAY CRYSTAL}, isbn = {1549-9618}, url = {The lack, of accurate transferable local pseudopotentials represents one of the remaining, barriers to the. general application of orbital-free density functional theory (OF-DFT, a linear scaling technique). Here we report a method to generate high quality ab initio local pseudopotentials (LPS\’s) for use in condensed matter DFT calculations. We exploit the first Hohenberg-Kohn theorem, which states that the external potential is, one-to-one mapped to the ground-state electron density. By employing a scheme for inverting the Kohn-Sham (KS) equations due to Wang and Parr, we iteratively solve for the KS effective potential v(eff)(KS)(r) until it reproduces a target density. From v(eff)(KS)(r) we derive a global LPS for the entire system. This global LPS is then further decomposed to obtain an atom-centered LPS. We show that LPS\’s,derived from bulk environments are substantially more transferable than those derived from atoms alone. In KS-DFT tests on Si, we show that this bulk-derived LPS can reproduce accurately phase orderings predicted by nonlocal pseudopotentials for both metallic and semiconducting phases. We then tested this LPS in OF-DFT calculations on Si crystals, where we demonstrate that this bulk-derived LPS (BLPS), combined with a linear-response-based kinetic energy density functional with a density-dependent kernel, correctly predicts a diamond structure ground state for Si in an OF-DFT calculation. Other bulk properties, such as defect formation energies and transition pressures are also presented as tests of this BLPS. This approach for deriving LPS\’s isolates much of the remaining error in OF-DFT to the kinetic energy density functional, providing means to test new functionals as they become available.

}, keywords = {CORRECT ASYMPTOTIC-BEHAVIOR, ELECTRONIC-STRUCTURE CALCULATIONS, ENERGY-DENSITY FUNCTIONALS, EXCHANGE-CORRELATION POTENTIALS, GROUND-STATE GEOMETRIES, INITIO MOLECULAR-DYNAMICS, KINETIC-ENERGY, NORM-CONSERVING PSEUDOPOTENTIALS, THOMAS-FERMI APPROXIMATION, WAVE-FUNCTIONS}, isbn = {1098-0121}, url = {