TY - JOUR
T1 - Characterization of the liquid Li-solid Mo (1 1 0) interface from classical molecular dynamics for plasma-facing applications
AU - Vella, Joseph R.
AU - Chen, Mohan
AU - Fürstenberg, Sven
AU - Stillinger, Frank H.
AU - Carter, Emily A.
AU - Debenedetti, Pablo G.
AU - Panagiotopoulos, Athanassios Z.
N1 - Funding Information:
The authors thank the Office of Fusion Energy Sciences, U.S. Department of Energy, which gave support for this work under Award DE-SC0008598. S. Fürstenberg would like to thank the Keller Center REACH Program for financial support. The authors are also grateful to the Terascale Infrastructure for Groundbreaking Research in Science and Engineering (TIGRESS) high performance computing center at Princeton University for computational resources.
Publisher Copyright:
© 2017 IAEA, Vienna.
PY - 2017/8/11
Y1 - 2017/8/11
N2 - An understanding of the wetting properties and a characterization of the interface between liquid lithium (Li) and solid molybdenum (Mo) are relevant to assessing the efficacy of Li as a plasma-facing component in fusion reactors. In this work, a new second-nearest neighbor modified embedded-atom method (2NN MEAM) force field is parameterized to describe the interactions between Li and Mo. The new force field reproduces several benchmark properties obtained from first-principles quantum mechanics simulations, including binding curves for Li at three different adsorption sites and the corresponding forces on Li atoms adsorbed on the Mo (1 1 0) surface. This force field is then used to study the wetting of liquid Li on the (1 1 0) surface of Mo and to examine the Li-Mo interface using molecular dynamics simulations. From droplet simulations, we find that liquid Li tends to completely wet the perfect Mo (1 1 0) surface, in contradiction with previous experimental measurements that found non-zero contact angles for liquid Li on a Mo substrate. However, these experiments were not carried out under ultra-high vacuum conditions or with a perfect (1 1 0) Mo surface, suggesting that the presence of impurities, such as oxygen, and surface structure play a crucial role in this wetting process. From thin-film simulations, it is observed that the first layer of Li on the Mo (1 1 0) surface has many solid-like properties such as a low mobility and a larger degree of ordering when compared to layers further away from the surface, even at temperatures well above the bulk melting temperature of Li. These findings are consistent with temperature-programmed desorption experiments.
AB - An understanding of the wetting properties and a characterization of the interface between liquid lithium (Li) and solid molybdenum (Mo) are relevant to assessing the efficacy of Li as a plasma-facing component in fusion reactors. In this work, a new second-nearest neighbor modified embedded-atom method (2NN MEAM) force field is parameterized to describe the interactions between Li and Mo. The new force field reproduces several benchmark properties obtained from first-principles quantum mechanics simulations, including binding curves for Li at three different adsorption sites and the corresponding forces on Li atoms adsorbed on the Mo (1 1 0) surface. This force field is then used to study the wetting of liquid Li on the (1 1 0) surface of Mo and to examine the Li-Mo interface using molecular dynamics simulations. From droplet simulations, we find that liquid Li tends to completely wet the perfect Mo (1 1 0) surface, in contradiction with previous experimental measurements that found non-zero contact angles for liquid Li on a Mo substrate. However, these experiments were not carried out under ultra-high vacuum conditions or with a perfect (1 1 0) Mo surface, suggesting that the presence of impurities, such as oxygen, and surface structure play a crucial role in this wetting process. From thin-film simulations, it is observed that the first layer of Li on the Mo (1 1 0) surface has many solid-like properties such as a low mobility and a larger degree of ordering when compared to layers further away from the surface, even at temperatures well above the bulk melting temperature of Li. These findings are consistent with temperature-programmed desorption experiments.
KW - liquid lithium
KW - liquid metals
KW - lithium wetting molybdenum
KW - molecular dynamics simulations
KW - molybdenum
KW - plasma-facing materials
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U2 - 10.1088/1741-4326/aa7e0d
DO - 10.1088/1741-4326/aa7e0d
M3 - Article
AN - SCOPUS:85028436386
SN - 0029-5515
VL - 57
JO - Nuclear Fusion
JF - Nuclear Fusion
IS - 11
M1 - 116036
ER -