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Random phase approximation

About: Random phase approximation is a research topic. Over the lifetime, 4202 publications have been published within this topic receiving 83067 citations.


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Journal ArticleDOI
TL;DR: An adiabatic-connection fluctuation-dissipation theorem approach based on a range separation of electron-electron interactions is proposed, which corrects several shortcomings of the standard random phase approximation and is particularly well suited for describing weakly bound van der Waals systems.
Abstract: An adiabatic-connection fluctuation-dissipation theorem approach based on a range separation of electron-electron interactions is proposed. It involves a rigorous combination of short-range densityfunctional and long-range random phase approximations. This method corrects several shortcomings of the standard random phase approximation and it is particularly well suited for describing weakly bound van der Waals systems, as demonstrated on the challenging cases of the dimers Be2 and Ne2.

256 citations

Journal ArticleDOI
TL;DR: In this article, the authors examined the excitation properties of spherical nuclei in the Random Phase Approximation using the Green's function method and found that the level of agreement with empirical properties is as follows: energies of low-lying states, ≈ 25%; positions of giant resonances, ≉ 10%; transition rates of low states, factor of 2 typical.

250 citations

Book ChapterDOI
Kurt Binder1
01 Jan 1994
TL;DR: In this paper, the authors discuss the conditions under which the linearized (Cahn-like) theory of spinodal decomposition holds for block copolymer melts, where chains may stretch out in a dumbbell-like shape even in disordered phase, before the microphase separation transition.
Abstract: The classical concepts about unmixing of polymer blends (Flory-Huggins theory) and about mesophase ordering in block copolymers (Leibler's theory) are briefly reviewed and their validity is discussed in the light of recent experiments, computer simulations and other theoretical concepts. It is emphasized that close to the critical point of unmixing non-classical critical exponents of the Ising universality class are observed, in contrast to the classical mean-field exponents implied by the Flory-Huggins theory. The temperature range of this non-mean-field behavior can be understood by Ginzburg criteria. The latter are also useful to discuss the conditions under which the linearized (Cahn-like) theory of spinodal decomposition holds. While Flory-Huggins theory predicts correctly that the critical value of the Flory χ-parameter scales with chain length N (for symmetrical mixtures) χc ∝ 1/N, it strongly overestimates the prefactor and its use for fitting experimental data yields spurious concentration dependence. Also the chain radii depend on both χ and the composition of the mixture, thus invalidating the random phase approximation (RPA). Particular strong deviations from the RPA are predicted for block copolymer melts, where chains may stretch out in a dumbbell-like shape even in the disordered phase, before the microphase separation transition is approached. This review concludes with an outlook on interfacial phenomena and surface effects on these systems and other open problems in this field.

247 citations

Journal ArticleDOI
TL;DR: It is shown that the Gaussian core model of particles interacting via a penetrable repulsive Gaussian potential behaves as a weakly correlated "mean-field fluid" over a surprisingly wide density and temperature range.
Abstract: We show that the Gaussian core model of particles interacting via a penetrable repulsive Gaussian potential, first considered by Stillinger [J. Chem. Phys. 65, 3968 (1976)], behaves as a weakly correlated "mean-field fluid" over a surprisingly wide density and temperature range. In the bulk, the structure of the fluid phase is accurately described by the random phase approximation for the direct correlation function, and by the more sophisticated hypernetted chain integral equation. The resulting pressure deviates very little from a simple mean-field-like quadratic form in the density, while the low density virial expansion turns out to have an extremely small radius of convergence. Density profiles near a hard wall are also very accurately described by the corresponding mean-field free-energy functional. The binary version of the model exhibits a spinodal instability against demixing at high densities. Possible implications for semidilute polymer solutions are discussed.

247 citations

Journal ArticleDOI
TL;DR: It is shown that the inclusion of second-order screened exchange to the random phase approximation allows for an accurate description of electronic correlation in atoms and solids clearly surpassing therandom phase approximation, but not yet approaching chemical accuracy.
Abstract: We show that the inclusion of second-order screened exchange to the random phase approximation allows for an accurate description of electronic correlation in atoms and solids clearly surpassing the random phase approximation, but not yet approaching chemical accuracy. From a fundamental point of view, the method is self-correlation free for one-electron systems. From a practical point of view, the approach yields correlation energies for atoms, as well as for the jellium electron gas within a few kcal/mol of exact values, atomization energies within typically 2–3 kcal/mol of experiment, and excellent lattice constants for ionic and covalently bonded solids (0.2% error). The computational complexity is only O(N5), comparable to canonical second-order Moller–Plesset perturbation theory, which should allow for routine calculations on many systems.

240 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202365
2022133
202183
202097
2019102
2018119