Monte Carlo studies of flow and transport in fractal conductivity fields: Comparison with stochastic perturbation theory

1997 ◽  
Vol 33 (11) ◽  
pp. 2519-2534 ◽  
Author(s):  
Ahmed E. Hassan ◽  
John H. Cushman ◽  
Jacques W. Delleur
Keyword(s):  
Monte Carlo ◽  
Perturbation Theory ◽  
Stochastic Perturbation ◽  
Flow And Transport ◽  
Monte Carlo Studies ◽  
Fractal Conductivity

scholarly journals Monte Carlo studies of pion distributions from heavy ion collisions

1983 ◽  
Vol 27 (2) ◽  
pp. 606-627 ◽  
Author(s):  
Hafez M. A. Radi ◽  
John O. Rasmussen ◽  
Kenneth A. Frankel ◽  
John P. Sullivan ◽  
H. C. Song
Keyword(s):  
Monte Carlo ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Ion Collisions ◽  
Monte Carlo Studies

scholarly journals Non-Covalent Forces in Naphthazarin—Cooperativity or Competition in the Light of Theoretical Approaches

2021 ◽  
Vol 22 (15) ◽  
pp. 8033
Author(s):  
Aneta Jezierska ◽  
Kacper Błaziak ◽  
Sebastian Klahm ◽  
Arne Lüchow ◽  
Jarosław J. Panek
Keyword(s):  
Monte Carlo ◽  
Perturbation Theory ◽  
Potential Energy ◽  
Proton Transfer ◽  
Ir Spectra ◽  
Quantum Monte Carlo ◽  
Density Functional ◽  
Theoretical Approaches ◽  
Study Results ◽  
Intramolecular Hydrogen

Non-covalent interactions responsible for molecular features and self-assembly in Naphthazarin C polymorph were investigated on the basis of diverse theoretical approaches: Density Functional Theory (DFT), Diffusion Quantum Monte Carlo (DQMC), Symmetry-Adapted Perturbation Theory (SAPT) and Car-Parrinello Molecular Dynamics (CPMD). The proton reaction paths in the intramolecular hydrogen bridges were studied. Two potential energy minima were found indicating that the proton transfer phenomena occur in the electronic ground state. Diffusion Quantum Monte Carlo (DQMC) and other levels of theory including Coupled Cluster (CC) employment enabled an accurate inspection of Potential Energy Surface (PES) and revealed the energy barrier for the proton transfer. The structure and reactivity evolution associated with the proton transfer were investigated using Harmonic Oscillator Model of Aromaticity - HOMA index, Fukui functions and Atoms In Molecules (AIM) theory. The energy partitioning in the studied dimers was carried out based on Symmetry-Adapted Perturbation Theory (SAPT) indicating that dispersive forces are dominant in the structure stabilization. The CPMD simulations were performed at 60 K and 300 K in vacuo and in the crystalline phase. The temperature influence on the bridged protons dynamics was studied and showed that the proton transfer phenomena were not observed at 60 K, but the frequent events were noticed at 300 K in both studied phases. The spectroscopic signatures derived from the CPMD were computed using Fourier transformation of autocorrelation function of atomic velocity for the whole molecule and bridged protons. The computed gas-phase IR spectra showed two regions with OH absorption that covers frequencies from 2500 cm−1 to 2800 cm−1 at 60 K and from 2350 cm−1 to 3250 cm−1 at 300 K for both bridged protons. In comparison, the solid state computed IR spectra revealed the environmental influence on the vibrational features. For each of them absorption regions were found between 2700–3100 cm−1 and 2400–2850 cm−1 at 60 K and 2300–3300 cm−1 and 2300–3200 cm−1 at 300 K respectively. Therefore, the CPMD study results indicated that there is a cooperation of intramolecular hydrogen bonds in Naphthazarin molecule.

scholarly journals Stochastic computation of g − 2 in QED

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ryuichiro Kitano ◽  
Hiromasa Takaura ◽  
Shoji Hashimoto
Keyword(s):  
Perturbation Theory ◽  
Numerical Computation ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Stochastic Perturbation ◽  
Higher Order ◽  
Feynman Diagrams ◽  
Perturbative Series ◽  
Physical Quantities

Abstract We perform a numerical computation of the anomalous magnetic moment (g − 2) of the electron in QED by using the stochastic perturbation theory. Formulating QED on the lattice, we develop a method to calculate the coefficients of the perturbative series of g − 2 without the use of the Feynman diagrams. We demonstrate the feasibility of the method by performing a computation up to the α3 order and compare with the known results. This program provides us with a totally independent check of the results obtained by the Feynman diagrams and will be useful for the estimations of not-yet-calculated higher order values. This work provides an example of the application of the numerical stochastic perturbation theory to physical quantities, for which the external states have to be taken on-shell.

Reverse Monte Carlo studies of nanoporous carbon from TiC

2005 ◽  
Vol 17 (23) ◽  
pp. 3509-3524 ◽  
Author(s):  
Per Zetterström ◽  
Sigita Urbonaite ◽  
Fredrik Lindberg ◽  
Robert G Delaplane ◽  
Jaan Leis ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Nanoporous Carbon ◽  
Reverse Monte Carlo ◽  
Monte Carlo Studies

Atomistic Kinetic Monte Carlo studies of microchemical evolutions driven by diffusion processes under irradiation

2010 ◽  
Vol 406 (1) ◽  
pp. 55-67 ◽  
Author(s):  
F. Soisson ◽  
C.S. Becquart ◽  
N. Castin ◽  
C. Domain ◽  
L. Malerba ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Diffusion Processes ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Studies
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