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.

Observation of Feshbach Resonances in the F+ H2 → HF +H Reaction

Abstract: Reaction resonances, or transiently stabilized transition-state structures, have proven highly challenging to capture experimentally. Here, we used the highly sensitive H atom Rydberg tagging time-of-flight method to conduct a crossed molecular beam scattering study of the F + H2 --> HF + H reaction with full quantum-state resolution. Pronounced forward-scattered HF products in the v' = 2 vibrational state were clearly observed at a collision energy of 0.52 kcal/mol; this was attributed to both the ground and the first excited Feshbach resonances trapped in the peculiar HF(v' = 3)-H' vibrationally adiabatic potential, with substantial enhancement by constructive interference between the two resonances.

Modeling ethanol decomposition on transition metals: a combined application of scaling and Brønsted-Evans-Polanyi relations.

Abstract: Applying density functional theory (DFT) calculations to the rational design of catalysts for complex reaction networks has been an ongoing challenge, primarily because of the high computational cost of these calculations. Certain correlations can be used to reduce the number and complexity of DFT calculations necessary to describe trends in activity and selectivity across metal and alloy surfaces, thus extending the reach of DFT to more complex systems. In this work, the well-known family of Bronsted-Evans-Polanyi (BEP) correlations, connecting minima with maxima in the potential energy surface of elementary steps, in tandem with a scaling relation, connecting binding energies of complex adsorbates with those of simpler ones (e.g., C, O), is used to develop a potential-energy surface for ethanol decomposition on 10 transition metal surfaces. Using a simple kinetic model, the selectivity and activity on a subset of these surfaces are calculated. Experiments on supported catalysts verify that this simple model is reasonably accurate in describing reactivity trends across metals, suggesting that the combination of BEP and scaling relations may substantially reduce the cost of DFT calculations required for identifying reactivity descriptors of more complex reactions.

Global geometry optimization of clusters using genetic algorithms

Abstract: A genetic algorithm is used to find the global minimum energy structure for Si 4 on an empirical potential energy surface. Given a suitable encoding of the cluster geometry, and an exponential scaling of the potential energy values to obtain a fitness function, the genetic algorithm can successfully optimize all degrees of freedom. With the number of potential energy function evaluations as a measure, the genetic algorithm is more economical than either a set of traditional, local minimizations or a molecular dynamics simulated annealing approach

Ab initio potential energy and dipole moment surfaces for H5O2

Abstract: Full-dimensional ab initio potential energy surface (PES) and dipole moment surface (DMS) are reported for H5O2+. Tens of thousands of coupled-cluster [CCSD(T)] and second-order Moller-Plesset (MP2) calculations of electronic energies, using aug-cc-pVTZ basis, were done. The energies were fit very precisely in terms of all the internuclear distances, using standard least-square procedures, however, with a fitting basis that satisfies permutational symmetry with respect to like atoms. The H5O2+ PES is a fit to 48 189 CCSD(T) energies, containing 7962 polynomial coefficients. The PES has a rms fitting error of 34.9 cm−1 for the entire data set up to 110 000 cm−1. This surface can describe various internal floppy motions, including the H atom exchanges, monomer inversions, and monomer torsions. First- and higher-order saddle points have been located on the surface and compared with available previous theoretical work. In addition, the PES dissociates correctly (and symmetrically) to H2O+H3O+, with De=11 923....