Quantum diffusion of H/D on Ni(111)—A partially adiabatic centroid MD study

TY - JOUR

T1 - Quantum diffusion of H/D on Ni(111)—A partially adiabatic centroid MD study

AU - Probert, Matthew Ian James

AU - Hopkinson, Aaron Russell

N1 - © 2018 AIP Publishing LLC. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2018/2/2

Y1 - 2018/2/2

N2 - We present the results of a theoretical study of H/D diffusion on a Ni(111) surface at a range of temperatures, from 250 K to 75 K. The diffusion is studied using both classical molecular dynamics and the partially adiabatic centroid molecular dynamics method. The calculations are performed with the hydrogen (or deuterium) moving in 3D across a static nickel surface using a novel Fourier interpolated potential energy surface which has been parameterized to density functional theory calculations. The results of the classical simulations are that the calculated diffusion coefficients are far too small and with too large a variation with temperature compared with experiment. By contrast, the quantum simulations are in much better agreement with experiment and show that quantum effects in the diffusion of hydrogen are significant at all temperatures studied. There is also a crossover to a quantum-dominated diffusive regime for temperatures below ∼150 K for hydrogen and ∼85 K for deuterium. The quantum diffusion coefficients are found to accurately reproduce the spread in values with temperature, but with an absolute value that is a little high compared with experiment.

AB - We present the results of a theoretical study of H/D diffusion on a Ni(111) surface at a range of temperatures, from 250 K to 75 K. The diffusion is studied using both classical molecular dynamics and the partially adiabatic centroid molecular dynamics method. The calculations are performed with the hydrogen (or deuterium) moving in 3D across a static nickel surface using a novel Fourier interpolated potential energy surface which has been parameterized to density functional theory calculations. The results of the classical simulations are that the calculated diffusion coefficients are far too small and with too large a variation with temperature compared with experiment. By contrast, the quantum simulations are in much better agreement with experiment and show that quantum effects in the diffusion of hydrogen are significant at all temperatures studied. There is also a crossover to a quantum-dominated diffusive regime for temperatures below ∼150 K for hydrogen and ∼85 K for deuterium. The quantum diffusion coefficients are found to accurately reproduce the spread in values with temperature, but with an absolute value that is a little high compared with experiment.

KW - path integral molecular dynamics

KW - hydrogen diffusion

KW - ab initio calculation

U2 - 10.1063/1.5004801

DO - 10.1063/1.5004801

M3 - Article

SN - 0021-9606

VL - 148

SP - 1

EP - 18

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

M1 - 102339

ER -