Thermal Gaussian molecular dynamics for quantum dynamics simulations of many-body systems: Application to liquid para-hydrogen

2011 ◽  
Vol 134 (17) ◽  
pp. 174109 ◽  
Author(s):  
Ionuţ Georgescu ◽  
Jason Deckman ◽  
Laura J. Fredrickson ◽  
Vladimir A. Mandelshtam
Keyword(s):  
Molecular Dynamics ◽  
Quantum Dynamics ◽  
Para Hydrogen ◽  
Many Body ◽  
Many Body Systems ◽  
Dynamics Simulations

Molecular Dynamics Simulation of Sputtering with Mmany-Body Interactions

1988 ◽  
Vol 100 ◽  
Author(s):  
Davy Y. Lo ◽  
Tom A. Tombrello ◽  
Mark H. Shapiro ◽  
Don E. Harrison
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Single Crystal ◽  
Low Energy ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Many Body ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Small Single Crystal

ABSTRACTMany-body forces obtained by the Embedded-Atom Method (EAM) [41 are incorporated into the description of low energy collisions and surface ejection processes in molecular dynamics simulations of sputtering from metal targets. Bombardments of small, single crystal Cu targets (400–500 atoms) in three different orientations ({100}, {110}, {111}) by 5 keV Ar+ ions have been simulated. The results are compared to simulations using purely pair-wise additive interactions. Significant differences in the spectra of ejected atoms are found.

scholarly journals Investigating Tunneling Controlled Chemical Reactions Through Ab-Initio Ring Polymer Molecular Dynamics

2021 ◽  
Author(s):  
Xinyang Li ◽  
Pengfei Huo
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Chemical Reaction ◽  
Quantum Tunneling ◽  
Quantum Dynamics ◽  
Density Functional ◽  
Molecular System ◽  
Ring Polymer ◽  
Ring Polymer Molecular Dynamics ◽  
Dynamics Simulations

<div>We use the ab-initio ring polymer molecular dynamics (RPMD) approach to investigate tunneling controlled reactions in methylhydroxycarbene. Nuclear tunneling effects enable molecules to overcome the barriers which can not be overcome classically. Under low-temperature conditions, intrinsic quantum tunneling effects canfacilitate the chemical reaction in a pathway that is neither favored thermodynamically nor kinetically. This</div><div>behavior is referred to as the tunneling controlled chemical reaction and regarded as the third paradigm of chemical</div><div>reaction controls. In this work, we use the ab-initio RPMD approach to incorporate the tunneling effects in our quantum dynamics simulations. The reaction kinetics of two competitive reaction pathways at various temperatures are investigated with the Kohn-Sham density functional theory (KS-DFT) on-the-fly molecular dynamics simulations and the ring polymer quantization of the nuclei. The reaction rate constants obtained here agree extremely well with the experimentally measured rates. We demonstrate the feasibility of using ab-initio RPMD rate calculations in a realistic molecular system, and provide an interesting and important example for future investigations on reaction mechanisms dominated by quantum tunneling effects.</div>

EFFECT OF CHIRALITY ON THE STABILITY OF CARBON NANOTUBES: MOLECULAR-DYNAMICS SIMULATIONS

2001 ◽  
Vol 12 (06) ◽  
pp. 865-870 ◽  
Author(s):  
ŞAKIR ERKOÇ ◽  
OSMAN BARIŞ MALCIOĞLU
Keyword(s):  
Heat Treatment ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Potential Energy Function ◽  
Single Wall Carbon Nanotubes ◽  
Many Body ◽  
Chiral Structure ◽  
The Stability ◽  
Dynamics Simulations ◽  
Body Potential

The effect of chirality on the structural stability of single-wall carbon nanotubes have been investigated by performing molecular-dynamics computer simulations. Calculations have been realized by using an empirical many-body potential energy function for carbon. It has been found that carbon nanotube in chiral structure is more stable under heat treatment relative to zigzag and armchair models. The diameter of the tubes is slightly enlarged under heat treatment.

Discrete Time Crystals

2020 ◽  
Vol 11 (1) ◽  
pp. 467-499 ◽  
Author(s):  
Dominic V. Else ◽  
Christopher Monroe ◽  
Chetan Nayak ◽  
Norman Y. Yao
Keyword(s):  
Discrete Time ◽  
Quantum Dynamics ◽  
Many Body ◽  
Time Translation ◽  
Translation Symmetry ◽  
Interesting Class ◽  
Many Body Systems ◽  
Definition Of ◽  
Many Body Interactions ◽  
Time Crystals

Experimental advances have allowed for the exploration of nearly isolated quantum many-body systems whose coupling to an external bath is very weak. A particularly interesting class of such systems is those that do not thermalize under their own isolated quantum dynamics. In this review, we highlight the possibility for such systems to exhibit new nonequilibrium phases of matter. In particular, we focus on discrete time crystals, which are many-body phases of matter characterized by a spontaneously broken discrete time-translation symmetry. We give a definition of discrete time crystals from several points of view, emphasizing that they are a nonequilibrium phenomenon that is stabilized by many-body interactions, with no analog in noninteracting systems. We explain the theory behind several proposed models of discrete time crystals, and compare several recent realizations, in different experimental contexts.

Molecular Dynamics Simulations of Atoms Diffusion in Solid

2018 ◽  
Vol 15 ◽  
pp. 51-64
Author(s):  
Yu Lu Zhou ◽  
Xiao Ma Tao ◽  
Qing Hou ◽  
Yi Fang Ouyang
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Md Simulations ◽  
Einstein Relation ◽  
Interatomic Potentials ◽  
Body System ◽  
Many Body ◽  
Point Particles ◽  
Bulk Surface ◽  
Dynamics Simulations

Molecular dynamics (MD) simulations, which treat atoms as point particles and trace their individual trajectories, are always employed to investigate the transport properties of a many-body system. The diffusion coefficients of atoms in solid can be obtained by the Einstein relation and the Green-Kubo relation. An overview of the MD simulations of atoms diffusion in the bulk, surface and grain boundary is provided. We also give an example of the diffusion of helium in tungsten to illustrate the procedure, as well as the importance of the choice of interatomic potentials. MD simulations can provide intuitive insights into the atomic mechanisms of diffusion.

Molecular Dynamics Simulations of Low-Energy Ion/Surface Interactions During Vapor Phase Crystal Growth: 10 eV Si Incident on Si(001)2×1

1989 ◽  
Vol 157 ◽  
Author(s):  
M. Kitabatake ◽  
P. Fons ◽  
J. E. Greene
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Unit Cell ◽  
Many Body ◽  
Energy Redistribution ◽  
Surface Unit ◽  
Phase Crystal ◽  
Dynamics Simulations ◽  
Body Potential ◽  
Surface Unit Cell

ABSTRACTMolecular dynamics simulations, utilizing the Tersoff many-body potential, were used to investigate the effects of 10 eV Si atom bombardment of a (001)2×1 terminated Si lattice. The irradiation events were initiated at an array of points in the primitive surface unit cell. Each event was followed to determine kinetic energy redistribution in the lattice as a function of time, projectile and lattice atom trajectories, and the nature, number, and depth of residual defects. Dimer breaking, epitaxial growth, position exchange, and the formation of residual hexagonal and split interstitials were observed. There were no residual vacancies. Impact points leading to each of the above results clustered in distinctly different regions of the surface unit cell. Bulk interstitials were annealed out over time scales corresponding to monolayer deposition during Si MBE.

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