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Showing 1 to 20 of 101 for “"potential energy surface"”.
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Potential Energy Surface around the Tropylium Ion.
… (2d) levels. This work will show areas of the potential energy surface around the highly symmetric tropylium ion to give a glance of possible mechanisms for its formation and decomposition. Our results have confirmed some of the mechanisms reported in the literature, and in addition new areas …
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Characterizing the potential energy surface of two dimensional and bulk materials using high dimensional neural network potentials
… a general mapping from atomic coordinates to the potential energy surface is obtained using a feed-forward artificial neural network. An approximate Density Functional Theory method, Density Functional Tight Binding (DFTB+), is used to compute quantities required for the reference dataset. It is …
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Vibrational Spectroscopy and Potential Energy Surface Analysis of the X˜ And B˜ States of Thiophosgene
… out-of-plane bending (nu4) modes, and extend in energy beyond the lowest molecular dissociation threshold. A full six-dimensional potential energy surface transformed to a normal coordinate representation has been fit to the experimental X˜(1 A1) levels up to 8,000 cm-1. A six-dimensional …
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Potential Energy Surfaces for Intermolecular Proton Transfers in Crystalline Aspirin: A Computational Study
… density functional theory were used to model the potential energy surface of intermolecular proton transfers in crystalline aspirin. Using these surfaces the importance of intermolecular interactions and excited states to the proton transfer were also explored. In addition, the ability of ab …
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Ab initio and Direct Quasiclassical Trajectory Study of the F + CH₄ → HF + CH₃ and F + C₂H₆ → HF + C₂H₅ Reactions
… and negates the need for an analytical potential energy surface when performing reaction dynamics studies. The reparametization of semiempirical Hamiltonians increases the agreement with experiment and high level ab initio theory. We have chosen to create one set of new parameters that …
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Product Basis Set Variational Calculations of Triatomic Rovibrational Energy Levels and Wavefunctions
If both the potential energy surface of a molecule and trial functions for a variational calculation are expanded in products of internal coordinate functions, the Hamiltonian matrix may be speedily built because all required integrals are one-dimensional. New methods, especially for calculating …
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The photochemical and mechanochemical ring opening of cyclobutene from first principles
… (MRCI). This provides us with a more accurate potential energy surface in which to run our dynamics on. We find that the stereochemistry for ring opening is determined on the ground state. We have also identified two S1/S0 intersections that could be relevant to the photochemical ring opening …
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Indices de reactividad y selectividad para caracterizar moléculas, clusters y reacciones químicas
Potential energy surface is a key concept in the application of electronic structure methods to the study of molecular structure, properties and reactivities, however its determination imply a high computational cost. The aim of this work is to apply the concepts and principles based upon Density …
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Physical models of protein folding within the energy landscape theory
The energy landscape theory of protein fol9.ing is based on a statistical description of a protein's complex potential energy surface. Individual folding events are sampled from an ensemble of possible routes on the landscape. The theory suggests that the landscape of a protein can be described as …
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The molecular dynamics of hydrogen-bonding explored with broadband two dimensional infrared spectroscopy
… evidence for large deformations of the nuclear potential energy surface, giving rise to extremely anharmonic and collective dynamics. The effect is most dramatic in liquid water, where the rapidly fluctuating hydrogen-bond network results in vibrational excitons wherein O-H stretching motion is …
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Photodissociation Dynamics In Titan's Atmosphere
… of cyanoacetylene at 193.3 nm proceeds on the S1 potential energy surface with an exit barrier. In heptane photodissociation, the dissociation occurs on the ground state or low-lying triplet states with nonradiative electronic relaxation. Time-of-flight mass spectroscopy studies in this system …
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Supersonic jet spectroscopy of synthetic foldamers, multichromophores, and their water containing clusters
… occurs along a simple reaction coordinate on the potential energy surface. Molecules in this regime benefit greatly from experiments probing the potential energy surfaces and provide a means to develop and test new theories in an effort to explain more complex system. These measurements are …
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Theoretical and experimental studies of energy transfer dynamics in collisions of atomic and molecular species with model organic surfaces
… of chemical reaction dynamics at the gas/organic-surface interface requires knowledge of energy-transfer processes that happen during the initial gas/surface collision. We have examined the influence of mass and rovibrational motion on the energy-transfer dynamics of gas-phase species scattering …
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Machine learning transferable physics-based force fields using graph convolutional neural networks
… properties of a system to be determined from its potential energy surface (PES). In the domain of crystalline materials, the PES is needed for electronic structure calculations, critical for modeling semiconductors, optical, and energy-storage materials. While first principles techniques can be …
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A tensor product decomposition of the many-electron Hamiltonian
… are presented. The preliminary ground state potential energy surface of the hydrogen molecule dimer is computed by the tensor product method using a small basis set.
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Dynamically motivated spectroscopy of small polyatomic molecules
… only perform well near local minima in the potential energy surface. Several spectroscopic techniques are developed and applied to the study of molecules in excited states, including chirped-pulse millimeter wave spectroscopy and adaptations of millimeter-wave optical double resonance. …
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Mid Infrared Investigation of Two Isomers of the CO-N2O van der Waals Complex
… OC-CO2. We show that the most recent ab initio potential energy surface is inadequate in predicting the intermolecular frequencies for both isomers (CO-N2O and OC-N2O).
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Computational Studies of Protonated Cyclic Ethers and Benzylic Organolithium Compounds
… lithium was studied computationally. Minimum-energy equilibrium geometries of explicit mono, bis and tris-solvated contact ion pairs (CIPs) and tetrakis-sovlated solvent separated ion pair (SSIPs) were modeled at B3LYP/6-31G*. Associative transition structures linking the tris-solvated CIPs …
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Computational modeling of organic structure, spectra, and reactivity
… systems. Modeling allows portions of the potential energy surface that cannot be examined experimentally, such as transition states. These transition states can lend themselves to better understanding of the system's reactivity. Modeling can also be used to perform analysis that would …
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Vibrational motion in thiophosgene and related studies
… likely due to the poor resolution of the higher energy spectrum. This made low-lying lines difficult to assign, thus hindering assignments of progressions in the higher region of this spectra. A higher resolution spectrum is required. A torsional potential energy surface was also constructed for …
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