Antisymmetric relation

About: Antisymmetric relation is a research topic. Over the lifetime, 3322 publications have been published within this topic receiving 64365 citations. The topic is also known as: antisymmetric property & anti-symmetric property.

A general structure factor formalism for interpreting accurate X-ray and neutron diffraction data

Abstract: The interpretation of X-ray and neutron diffraction data in accurate studies of crystal and molecular structure requires the development of a new structure factor formalism. The formalism normally employed in structure analysis fails to recognize antisymmetric features associated with nonspherical atomic charge distributions and with anharmonic components of the atomic vibration amplitudes. Both these antisymmetric features can be incorporated readily in the analysis of diffraction data by using a general formalism involving complex atomic scattering factors and complex temperature factors. Some implications of the general formalism are discussed. Relations between atomic motions and static positions are considered in terms of equilibrium and time-averaged concepts, and the case of librational motion is cited to illustrate the relation of these concepts to the type of vibrational approximation employed in data analysis. The discussion is extended to general considerations of the atomic scattering powers, and approximations in the customary handling of these quantities are noted.

Signatures of collisionless magnetic reconnection

Abstract: [1] Simulations of magnetic reconnection in simple systems without a guide field predict the formation of a spatially antisymmetric out-of-plane magnetic field signature and a symmetric perturbation in the plasma pressure. Here we show, using two fluid simulations and analytic arguments, that these signatures are not in fact a generic feature of fast reconnection. Rather, in the strong guide field limit the pressure perturbation becomes antisymmetric, while the perturbation in the out-of-plane field can be either symmetric for βx ∼ 1 or antisymmetric for βx ≫ 1, where βx is the plasma β defined using the reconnection magnetic field just upstream of the reconnection region.

Comparison of Three-Dimensional Flexible Beam Elements for Dynamic Analysis: Classical Finite Element Formulation and Absolute Nodal Coordinate Formulation

Abstract: Three formulations for a flexible spatial beam element for dynamic analysis are compared: a Timoshenko beam with large displacements and rotations, a fully parametrized element according to the absolute nodal coordinate formulation (ANCF), and an ANCF element based on an elastic line approach. In the last formulation, the shear locking of the antisymmetric bending mode is avoided by the application of either the two-field Hellinger‐Reissner or the three-field Hu‐Washizu variational principle. The comparison is made by means of linear static deflection and eigenfrequency analyses on stylized problems. It is shown that the ANCF fully parametrized element yields too large torsional and flexural rigidities, and shear locking effectively suppresses the antisymmetric bending mode. The presented ANCF formulation with the elastic line approach resolves most of these problems. DOI: 10.1115/1.4000320

The Jastrow antisymmetric geminal power in Hilbert space: Theory, benchmarking, and application to a novel transition state

Abstract: The Jastrow-modified antisymmetric geminal power (JAGP) ansatz in Hilbert space successfully overcomes two key failings of other pairing theories, namely, a lack of inter-pair correlations and a lack of multiple resonance structures, while maintaining a polynomially scaling cost, variational energies, and size consistency. Here, we present efficient quantum Monte Carlo algorithms that evaluate and optimize the JAGP energy for a cost that scales as the fifth power of the system size. We demonstrate the JAGP’s ability to describe both static and dynamic correlation by applying it to bond stretching in H2O, C2, and N2 as well as to a novel, multi-reference transition state of ethene. JAGP’s accuracy in these systems outperforms even the most sophisticated single-reference methods and approaches that of exponentially scaling active space methods.