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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 authors showed that mode specificity in unimolecular reaction dynamics is not determined solely by the quasiperiodic/ergodic character of the intramolecular mechanics.
Abstract: Energies and lifetimes (with respect to tunneling) for metastable states of the Henon–Heiles potential energy surface [V(x,y) = 1/2x2−1/3x3+1/2y2+xy2] have been computed quantum mechanically (via the method of complex scaling). This is a potential surface for which the classical dynamics is known to change from quasiperiodic at low energies to ergodic‐like at higher energies. The rate constants (i.e., inverse lifetimes) for unimolecular decay as a function of energy, however, are seen to be well described by standard statistical theory (microcanonical transition state theory, RRKM plus tunneling) over the entire energy region. This is thus another example indicating that mode specificity in unimolecular reaction dynamics is not determined solely by the quasiperiodic/ergodic character of the intramolecular mechanics.

77 citations

Journal ArticleDOI
TL;DR: The authors present diabatic and adiabatic potential energy surfaces for the three lowest electronic singlet states of H3+.
Abstract: The authors present diabatic and adiabatic potential energy surfaces for the three lowest electronic singlet states of H3+. The modeling of the surfaces is based on the multi-sheeted double many-body expansion method which consists of dressing the various matrix elements of the diatomics-in-molecules potential matrix with three-body terms. The avoided crossing between the two lowest states and the conical intersection between the second and the third state are accurately represented by construction.

77 citations

Journal ArticleDOI
TL;DR: In this paper, the complex potential energy surface for the unimolecular isomerization and dissociation of nitromethane (CH3NO2) was investigated theoretically at the G2MP2/B3LYP/6-311++G(2d,2p) level of theory.
Abstract: The complex potential energy surface for the unimolecular isomerization and dissociation of nitromethane (CH3NO2), including 10 CH3NO2 isomers, 46 interconversion transition states, and 16 major dissociation products, is probed theoretically at the G2MP2//B3LYP/6-311++G(2d,2p) level of theory. The geometries and relative energies for various stationary points are determined and are in good agreement with the available experimental values. Based on the calculated G2MP2 potential energy surface, the possible nitromethane unimolecular decomposition mechanism is discussed. It is shown that the most feasible decomposition channels for CH3NO2 are those that lead to 2CH3 + 2NO2, 2CH3O + 2NO, H2CO + HNO, and HCNO + H2O, respectively. Among them, 2CH3 and 2NO2 are produced by the direct C−N bond rupture of nitromethane, while the formation of the latter three products is initiated by CH3NO2 rearranging first to methyl nitrite or to aci-nitromethane. The C−N bond dissociation energy for nitromethane is calculated t...

77 citations

Journal ArticleDOI
TL;DR: In this paper, it is pointed out that it is more advantageous to express the Franck-Condon factors in terms of the gradient of the final state potential energy surface at the equilibrium geometry of the initial electronic state.
Abstract: In the customary calculation of vibrational intensity distribution in electronic spectra of polyatomic molecules, the Franck-Condon factors are expressed in terms of the difference of the equilibrium geometries of the initial and the final state. It is pointed out that it is more advantageous to express the Franck-Condon factors in terms of the gradient of the final state potential energy surface at the equilibrium geometry of the initial electronic state. The ionization and excitation of the NH3 molecule are considered to illustrate this fact. Although the change in geometry is known accurately in this case, rather poor Franck-Condon factors are obtained with the customary harmonic method. Remarkably enough, even the use of anharmonic potential energy functions, though rather laborious, does not improve the situation. The reason for this failure is discussed. Expanding, on the other hand, the final state potential energy around the initial state equilibrium geometry, we obtain satisfactory Franck-Condon ...

76 citations

Journal ArticleDOI
TL;DR: In this article, a simple method is described to adjust a potential energy surface to improve agreement with experiment and an application is made to the ab initio HCO potential energy surfaces.
Abstract: A simple method is described to adjust a potential energy surface to improve agreement with experiment. An application is made to the ab initio HCO potential energy surface.(AIP)

76 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023128
2022206
2021288
2020322
2019295
2018310