Potential energy surface

About: Potential energy surface is a research topic. Over the lifetime, 11674 publications have been published within this topic receiving 307691 citations.

Six-dimensional quantum dynamics of adsorption and desorption of H2 at Pd(100): Steering and steric effects.

Abstract: We report the first six-dimensional quantum dynamical calculations of dissociative adsorption and associative desorption. Using a potential energy surface obtained by density functional theory calculations, we show that the increase of the sticking probability with decreasing kinetic energy at low kinetic energies in the system ${\mathrm{H}}_{2}/\mathrm{Pd}(100)$, which is usually attributed to the existence of a molecular adsorption state, is due to dynamical steering. In addition, we examine the influence of rotational motion and orientation of the hydrogen molecule on adsorption and desorption.

Development of a "First Principles" Water Potential with Flexible Monomers. II: Trimer Potential Energy Surface, Third Virial Coefficient, and Small Clusters.

Abstract: A full-dimensional potential energy function (MB-pol) for simulations of water from the dimer to bulk phases is developed entirely from “first principles” by building upon the many-body expansion of the interaction energy. Specifically, the MB-pol potential is constructed by combining a highly accurate dimer potential energy surface [J. Chem. Theory Comput. 2013, 9, 5395] with explicit three-body and many-body polarization terms. The three-body contribution, expressed as a combination of permutationally invariant polynomials and classical polarizability, is derived from a fit to more than 12000 three-body energies calculated at the CCSD(T)/aug-cc-pVTZ level of theory, imposing the correct asymptotic behavior as predicted from “first principles”. Here, the accuracy of MB-pol is demonstrated through comparison of the calculated third virial coefficient with the corresponding experimental data as well as through analysis of the relative energy differences of small clusters.

Potential Energy Hypersurfaces

Abstract: 1. The Molecular Energy Expectation Value. Energy, the fundamental quantum mechanical observable. The Born-Oppenheimer approximation and the concept of nuclear geometry. Generalizations of nuclear coordinates. Global and local coordinate systems and the concept of nuclear configuration space. Intersections of Energy Hypersurfaces: adiabatic and diabatic representations. 2. Geometrical Properties of Energy Hypersurfaces. Energy derivatives: forces and force constants. Minima, saddle points and general critical points. Minimum energy path and the intrinsic reaction coordinate. Differential geometry of energy hypersurfaces. 3. Calculation and Representation of Energy Hypersurfaces. The Hartree-Fock-Roothaan-Hall method for the calculation of molecular wavefunctions. The electron correlation problem and the correlation energy. Calculation of semiempirical and empirical potential functions. The force method and calculation of higher derivatives. Minimum search methods for the determination of stable chemical species. Saddle point search methods for the determination of transition structures. Fitting of potential energy hypersurfaces, polynomials, splines and trigonometric functions. 4. The Quantum Chemical Concept of Molecules Revisited. Quantization and continuity. Wave packet topology. The topology of nuclear configurations. 5. Molecular Topology. The reduced nuclear configuration space: metric space M. Catchment regions of potential energy hypersurfaces: the representation of chemical species. Manifold theory of potential energy surfaces and catchment regions. Potential defying chemical species. The role of nuclear charges and relations between potential surfaces: convexity theorems in space w Z. Catchment regions and symmetry. 6. Reaction Topology. Topological reaction paths and quantum chemical reaction mechanisms. The algebraic structure of the complete set of reaction paths. The fundamental group of reaction mechanisms. The reaction globe, the reaction polyhedron, and homology group theory of reaction mechanisms. Quantum chemical reaction networks. The future of computer based quantum chemical synthesis design and molecular engineering. Appendix 1: Review of topological concepts. Appendix 2: Physical units and conversion factors. References. Subject Index.

Chemically accurate simulation of a prototypical surface reaction: H2 dissociation on Cu(111).

Abstract: Methods for accurately computing the interaction of molecules with metal surfaces are critical to understanding and thereby improving heterogeneous catalysis. We introduce an implementation of the specific reaction parameter (SRP) approach to density functional theory (DFT) that carries the method forward from a semiquantitative to a quantitative description of the molecule-surface interaction. Dynamics calculations on reactive scattering of hydrogen from the copper (111) surface using an SRP-DFT potential energy surface reproduce data on the dissociative adsorption probability as a function of incidence energy and reactant state and data on rotationally inelastic scattering with chemical accuracy (within ~4.2 kilojoules per mole).