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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.
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TL;DR: In this article, the dynamics for the H+CH4→H2+CH3 reaction was studied using reduced dimensionality quantum-mechanical theory, where the vibrational modes of ν1 and ν4 of CH4, the stretching vibration of H2, and the umbrella ν2 mode of CH3 were taken into account in the reaction dynamics based on the vibrual analysis along the reaction path.
Abstract: The dynamics for the H+CH4→H2+CH3 reaction has been studied using reduced dimensionality quantum‐mechanical theory. The system is treated as a linear four‐atom chemical reaction, reducing the system to a three‐dimensional scattering problem. The vibrational modes of ν1 and ν4 of CH4, the stretching vibration of H2, and the umbrella ν2 mode of CH3 are taken into consideration in the reaction dynamics based on the vibrational analysis along the reaction path. The semiempirical potential energy surface which has recently been developed by Jordan and Gilbert [J. Chem. Phys. 102, 5669 (1995)] is employed. Rotationally averaged cross sections and thermal rate constants are calculated using an energy‐shifting approximation in order to take into account the effect of all the degrees of freedom. It is shown that excitation of the ν1 mode of CH4 significantly enhances the reactivity, indicating that there is a strong coupling between the ν1 mode of CH4 and the reaction coordinate. The vibrational state distribution...
95 citations
TL;DR: The Born−Oppenheimer potential energy surface (BOPES) underlies theoretical and computational chemistry (whether one considers a single or multiply coupled surfaces) as discussed by the authors, and the recent progress in representing these surfaces, rigorously obtained from electronic structure calculations, is the focus of this Perspective.
Abstract: The Born−Oppenheimer potential energy surface(s) underlies theoretical and computational chemistry (whether one considers a single or multiply coupled surfaces). The recent progress in representing these surfaces, rigorously obtained from electronic structure calculations, is the focus of this Perspective. Examples of potentials of complex molecules, namely, CH3CHO, CH5+, and H5+, and molecular complexes, namely, water clusters, are given.
95 citations
TL;DR: The energy and properties of the zero-point state are focused on in the rigorous DMC calculations and variational calculations in full dimensionality for selected vibrational states of H(5)O(2) (+) using a new ab initio potential energy surface.
Abstract: We report quantum diffusion Monte Carlo (DMC) and variational calculations in full dimensionality for selected vibrational states of H(5)O(2) (+) using a new ab initio potential energy surface [X. Huang, B. Braams, and J. M. Bowman, J. Chem. Phys. 122, 044308 (2005)]. The energy and properties of the zero-point state are focused on in the rigorous DMC calculations. OH-stretch fundamentals are also calculated using "fixed-node" DMC calculations and variationally using two versions of the code MULTIMODE. These results are compared with infrared multiphoton dissociation measurements of Yeh et al. [L. I. Yeh, M. Okumura, J. D. Myers, J. M. Price, and Y. T. Lee, J. Chem. Phys. 91, 7319 (1989)]. Some preliminary results for the energies of several modes of the shared hydrogen are also reported.
95 citations
TL;DR: A survey of 14 years of theoretical work on the FH/sub 2/ potential energy hypersurface can be found in this paper, where the importance of zero-point vibrational corrections and tunneling corrections in reliable predictions of the same activation energy is discussed.
Abstract: This account surveys 14 years of more or less continuing theoretical research on the FH/sub 2/ potential energy hypersurface. Early encouragement concerning the ability of theory to reliably characterize the entrance barrier for F + H/sub 2/ ..-->.. FH + H has more recently been sobered by the realization that very high levels of theory are required for this task. The importance of zero-point vibrational corrections and tunneling corrections in reliable predictions of the same activation energy is discussed. In contrast, the barrier height of H + FH ..-->.. HF + H three-center exchange stands as a prominent early success of ab initio molecular electronic structure theory. 90 references, 4 figures, 6 tables.
95 citations
TL;DR: In this paper, a new TS optimization method has been proposed on a multidimensional free energy surface (FES), which utilizes force and Hessian on the FES, which can be calculated by molecular dynamics method and the free energy perturbation theory.
Abstract: To obtain a transition state (TS) in solution chemical reaction, a new TS optimization method has been proposed on a multidimensional free energy surface (FES). Analogous to the method for the Born–Oppenheimer potential energy surface using ab initio molecular orbital calculation, the present method utilizes force and Hessian on the FES, which can be calculated by molecular dynamics method and the free energy perturbation theory. Furthermore, on the basis of the method, we have proposed the definition of the intrinsic reaction coordinate (IRC) on the FES. According to not only the estimation of the computational demand but also the comparison of the numerical accuracy, we conclude that our method should be more efficient than such other methods that utilize only the free energy. Finally, it is discussed that the TS optimization and the IRC on the FES should become very important tools to develop a new research field called the solution chemical reaction ergodography. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 95–103, 1998
95 citations