The Experts below are selected from a list of 37830 Experts worldwide ranked by ideXlab platform
Alex J. W. Thom - One of the best experts on this subject based on the ideXlab platform.
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Holomorphic Hartree–Fock Theory: An Inherently Multireference Approach
Journal of chemical theory and computation, 2015Co-Authors: Hugh G. A. Burton, Alex J. W. ThomAbstract:We investigate the existence of holomorphic Hartree–Fock solutions using a revised SCF algorithm. We use this algorithm to study the Hartree–Fock solutions for H2 and H42+ and report the emergence of holomorphic solutions at Points of Symmetry breaking. Finally, we find these holomorphic solutions for H4 and use them as a basis for Non-Orthogonal Configuration Interaction at a range of rectangular geometries and show them to produce energies in good agreement with Full Configuration Interaction.
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Holomorphic Hartree-Fock theory: an inherently multireference approach
arXiv: Chemical Physics, 2015Co-Authors: Hugh G. A. Burton, Alex J. W. ThomAbstract:We investigate the existence of holomorphic Hartree-Fock solutions using a revised SCF algorithm. We use this algorithm to study the Hartree-Fock solutions for H$_{2}$ and H$_{4}^{2+}$ and report the emergence of holomorphic solutions at Points of Symmetry breaking. Finally, we find these holomorphic solutions for H$_{4}$ and use them as a basis for Non-Orthogonal Configuration Interaction at a range of rectangular geometries and show them to produce energies in good agreement with Full Configuration Interaction.
Hugh G. A. Burton - One of the best experts on this subject based on the ideXlab platform.
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Holomorphic Hartree–Fock Theory: An Inherently Multireference Approach
Journal of chemical theory and computation, 2015Co-Authors: Hugh G. A. Burton, Alex J. W. ThomAbstract:We investigate the existence of holomorphic Hartree–Fock solutions using a revised SCF algorithm. We use this algorithm to study the Hartree–Fock solutions for H2 and H42+ and report the emergence of holomorphic solutions at Points of Symmetry breaking. Finally, we find these holomorphic solutions for H4 and use them as a basis for Non-Orthogonal Configuration Interaction at a range of rectangular geometries and show them to produce energies in good agreement with Full Configuration Interaction.
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Holomorphic Hartree-Fock theory: an inherently multireference approach
arXiv: Chemical Physics, 2015Co-Authors: Hugh G. A. Burton, Alex J. W. ThomAbstract:We investigate the existence of holomorphic Hartree-Fock solutions using a revised SCF algorithm. We use this algorithm to study the Hartree-Fock solutions for H$_{2}$ and H$_{4}^{2+}$ and report the emergence of holomorphic solutions at Points of Symmetry breaking. Finally, we find these holomorphic solutions for H$_{4}$ and use them as a basis for Non-Orthogonal Configuration Interaction at a range of rectangular geometries and show them to produce energies in good agreement with Full Configuration Interaction.
Heng Fan - One of the best experts on this subject based on the ideXlab platform.
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Diagonal Entropy and Topological Phase Transitions in Extended Kitaev Chains.
Annals of Physics, 2019Co-Authors: Hong Qiao, Zheng-hang Sun, Feng-xiao Sun, Heng FanAbstract:We investigate the diagonal entropy for ground states of the extended Kitaev chains with extensive pairing and hopping terms. The systems contain rich topological phases equivalently represented by topological invariant winding numbers and Majorana zero modes. Both the finite size scaling law and block scaling law of the diagonal entropy are studied, which indicates that the diagonal entropy demonstrates volume effect. The parameter of volume term is regarded as the diagonal entropy density, which can identify the critical Points of Symmetry-protected topological phase transitions efficiently in the studied models, even for those with higher winding numbers. The formulation of block scaling law and the capability of diagonal entropy density in detecting topological phase transitions are independent of the chosen bases. In order to manifest the advantage of diagonal entropy, we also calculate the global entanglement, which can not show clear signatures of the topological phase transitions. This work provides a new quantum-informatic approach to characterize the feature of the topologically ordered states and may motivate a deep understanding of the quantum coherence and diagonal entropy in various condensed matter systems.
Henry F. Schaefer - One of the best experts on this subject based on the ideXlab platform.
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A contribution to the understanding of the structure of xenon hexafluoride
The Journal of Chemical Physics, 1995Co-Authors: T. Daniel Crawford, Kristen W. Springer, Henry F. SchaeferAbstract:Three stationary Points of Symmetry C3v, C2v, and Oh on the potential energy surface of XeF6 have been located and characterized at the self‐consistent field level of theory with a large basis set. At this level of theory, and contrary to results given earlier in the literature, two of these stationary Points (C2v and Oh) are determined to be transition states, with harmonic vibrational frequencies leading to the third stationary point (C3v). In addition, second‐order Mo/ller–Plesset perturbation theory, configuration interaction, and coupled‐cluster energies have been determined at each of these optimized geometries. The C3v structure is predicted to lie lowest, followed by the C2v and then the Oh structure.
Graham A. Worth - One of the best experts on this subject based on the ideXlab platform.
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Conical intersections: A perspective on the computation of spectroscopic Jahn-Teller parameters and the degenerate 'intersection space'.
Physical chemistry chemical physics : PCCP, 2005Co-Authors: Martin J. Paterson, Michael J. Bearpark, Michael A. Robb, Lluís Blancafort, Graham A. WorthAbstract:We present a perspective on the computation and interpretation of force constants at Points of Symmetry-induced (Jahn-Teller) conical intersection. Our method is based upon the projection of the 'branching space' from the full (3N - 6)-dimensional Hessian for each component of a degenerate electronic state. For Jahn-Teller active molecules, this has the effect of removing the linear Jahn-Teller coupling from all but the interstate coupling and gradient difference vectors. The quadratic coupling constants are determined by the splitting of the harmonic vibrational frequencies within degenerate vibrational normal coordinates of the 'intersection space'. The potential energy surface topology along these normal modes is analogous to the Renner-Teller effect occurring in orbitally degenerate linear molecules. Our methodology gives a straightforward theoretical analysis of the various Jahn-Teller intersections and allows the determination of the seam curvature. Thus, we are in a position to compute the various Jahn-Teller coupling constants, in a particular coordinate system, and in addition to determine the nature of the high-Symmetry Jahn-Teller geometry (i.e., minimum or saddle-point on the seam). We illustrate these concepts with various examples of different Jahn-Teller conical intersections in some small molecules.