Capturing the nuclear quantum effects in molecular dynamics for lattice thermal conductivity calculations: Using ice as example

2020 ◽  
Vol 153 (19) ◽  
pp. 194105
Author(s):  
Ripeng Luo ◽  
Kuang Yu
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Lattice Thermal Conductivity ◽  
Quantum Effects ◽  
Nuclear Quantum Effects

scholarly journals Nuclear quantum effects in thermal conductivity from centroid molecular dynamics

2021 ◽  
Vol 154 (17) ◽  
pp. 174104
Author(s):  
Benjamin J. Sutherland ◽  
William H. D. Moore ◽  
David E. Manolopoulos
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Quantum Effects ◽  
Nuclear Quantum Effects

scholarly journals Sensitivity of Intra- and Intermolecular Interactions of Benzo[h]quinoline from Car–Parrinello Molecular Dynamics and Electronic Structure Inspection

2021 ◽  
Vol 22 (10) ◽  
pp. 5220
Author(s):  
Jarosław J. Panek ◽  
Joanna Zasada ◽  
Bartłomiej M. Szyja ◽  
Beata Kizior ◽  
Aneta Jezierska
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Quantum Effects ◽  
Potential Of Mean Force ◽  
Probability Density Distribution ◽  
Donor And Acceptor ◽  
Nuclear Quantum Effects ◽  
Vibrational Features

The O-H...N and O-H...O hydrogen bonds were investigated in 10-hydroxybenzo[h]quinoline (HBQ) and benzo[h]quinoline-2-methylresorcinol complex in vacuo, solvent and crystalline phases. The chosen systems contain analogous donor and acceptor moieties but differently coupled (intra- versus intermolecularly). Car–Parrinello molecular dynamics (CPMD) was employed to shed light onto principle components of interactions responsible for the self-assembly. It was applied to study the dynamics of the hydrogen bonds and vibrational features as well as to provide initial geometries for incorporation of quantum effects and electronic structure studies. The vibrational features were revealed using Fourier transformation of the autocorrelation function of atomic velocity and by inclusion of nuclear quantum effects on the O-H stretching solving vibrational Schrödinger equation a posteriori. The potential of mean force (Pmf) was computed for the whole trajectory to derive the probability density distribution and for the O-H stretching mode from the proton vibrational eigenfunctions and eigenvalues incorporating statistical sampling and nuclear quantum effects. The electronic structure changes of the benzo[h]quinoline-2-methylresorcinol dimer and trimers were studied based on Constrained Density Functional Theory (CDFT) whereas the Electron Localization Function (ELF) method was applied for all systems. It was found that the bridged proton is localized on the donor side in both investigated systems in vacuo. The crystalline phase simulations indicated bridged proton-sharing and transfer events in HBQ. These effects are even more pronounced when nuclear quantization is taken into account, and the quantized Pmf allows the proton to sample the acceptor area more efficiently. The CDFT indicated the charge depletion at the bridged proton for the analyzed dimer and trimers in solvent. The ELF analysis showed the presence of the isolated proton (a signature of the strongest hydrogen bonds) only in some parts of the HBQ crystal simulation. The collected data underline the importance of the intramolecular coupling between the donor and acceptor moieties.

Study of lattice thermal conductivity of tungsten containing bubbles by molecular dynamics simulation

2020 ◽  
Vol 161 ◽  
pp. 112004
Author(s):  
Hongyu Zhang ◽  
Jizhong Sun ◽  
Yingmin Wang ◽  
Thomas Stirner ◽  
Ali Y. Hamid ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Lattice Thermal Conductivity ◽  
Dynamics Simulation

Atomistic Level Molecular Dynamics Analysis and its Integrity in the Interim of Irradiation

2021 ◽  
Vol 318 ◽  
pp. 39-47
Author(s):  
Ahli K.D. Willie ◽  
Hong Tao Zhao ◽  
M. Annor-Nyarko
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Mixed Oxide ◽  
Md Simulation ◽  
Lattice Thermal Conductivity ◽  
Gas Diffusion ◽  
Mixed Oxide Fuel ◽  
Fission Gas ◽  
Increasing Temperature ◽  
End Members

In this work, molecular dynamics (MD) simulation was utilized in relation to access the thermal conductivity of UO2, PuO2 and (U, Pu)O2 in temperature range of 500–3000 K. Diffusion study on mixed oxide (MOX) was also performed to assess the effect of radiation damage by heavy ions at burnup temperatures. Analysis of the lattice thermal conductivity of irradiated MOX to its microstructure was carried out to enhance the irradiation defects with how high burnup hinders fuel properties and its pellet-cladding interaction. Fission gas diffusion as determined was mainly modelled by main diffusion coefficient. Degradation of diffusivity is predicted in MOX as composition deviate from the pure end members. The concentration of residual anion defects is considerably higher than that of cations in all oxides. Depending on the diffusion behavior of the fuel lattice, there was decrease in the ratio of anion to cation defects with increasing temperature. Besides, the modern mixed oxide fuel releases fission gas compared to that of UO2 fuel at moderate burnups.

scholarly journals On-the-Fly Ring-Polymer Molecular Dynamics Calculations of the Dissociative Photodetachment Process of the Oxalate Anion

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7250
Author(s):  
Yukinobu Takahashi ◽  
Yu Hashimoto ◽  
Kohei Saito ◽  
Toshiyuki Takayanagi
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Quantum Effects ◽  
Experimental Spectrum ◽  
Computational Time ◽  
Oxalate Anion ◽  
Dissociative Photodetachment ◽  
Ring Polymer ◽  
Ring Polymer Molecular Dynamics ◽  
Nuclear Quantum Effects

The dissociative photodetachment dynamics of the oxalate anion, C2O4H− + hν → CO2 + HOCO + e−, were theoretically studied using the on-the-fly path-integral and ring-polymer molecular dynamics methods, which can account for nuclear quantum effects at the density-functional theory level in order to compare with the recent experimental study using photoelectron–photofragment coincidence spectroscopy. To reduce computational time, the force acting on each bead of ring-polymer was approximately calculated from the first and second derivatives of the potential energy at the centroid position of the nuclei beads. We find that the calculated photoelectron spectrum qualitatively reproduces the experimental spectrum and that nuclear quantum effects are playing a role in determining spectral widths. The calculated coincidence spectrum is found to reasonably reproduce the experimental spectrum, indicating that a relatively large energy is partitioned into the relative kinetic energy between the CO2 and HOCO fragments. This is because photodetachment of the parent anion leads to Franck–Condon transition to the repulsive region of the neutral potential energy surface. We also find that the dissociation dynamics are slightly different between the two isomers of the C2O4H− anion with closed- and open-form structures.

The effect of molecular dynamics sampling on the calculated observable gas-phase structures

2016 ◽  
Vol 18 (27) ◽  
pp. 18237-18245 ◽  
Author(s):  
Denis S. Tikhonov ◽  
Arseniy A. Otlyotov ◽  
Vladimir V. Rybkin
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Gas Phase ◽  
Sampling Methods ◽  
Quantum Effects ◽  
Phase Structures ◽  
Nuclear Quantum Effects

We evaluate the performance of various ab initio molecular dynamics sampling methods for the calculation of observable gas-phase structures and probe the nuclear quantum effects.

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