TY  - JOUR
A1  - Mullan, Thomas
A1  - Maschio, Lorenzo
A1  - Saalfrank, Peter
A1  - Usvyat, Denis
T1  - Reaction barriers on non-conducting surfaces beyond periodic local MP2
BT  - Diffusion of hydrogen on alpha-Al2O3 (0001) as a test case
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - The quest for "chemical accuracy" is becoming more and more demanded in the field of structure and kinetics of molecules at solid surfaces. In this paper, as an example, we focus on the barrier for hydrogen diffusion on a alpha-Al2O3 (0001) surface, aiming for a couple cluster singles, doubles, and perturbative triples [CCSD(T)]-level benchmark. We employ the density functional theory (DFT) optimized minimum and transition state structures reported by Heiden, Usvyat, and Saalfrank [J. Phys. Chem. C 123, 6675 (2019)]. The barrier is first evaluated at the periodic Hartree-Fock and local Moller-Plesset second-order perturbation (MP2) level of theory. The possible sources of errors are then analyzed, which includes basis set incompleteness error, frozen core, density fitting, local approximation errors, as well as the MP2 method error. Using periodic and embedded fragment models, corrections to these errors are evaluated. In particular, two corrections are found to be non-negligible (both from the chemical accuracy perspective and at the scale of the barrier value of 0.72 eV): the correction to the frozen core-approximation of 0.06 eV and the CCSD(T) correction of 0.07 eV. Our correlated wave function results are compared to barriers obtained from DFT. Among the tested DFT functionals, the best performing for this barrier is B3LYP-D3.
Y1  - 2022
U6  - https://doi.org/10.1063/5.0082805
SN  - 0021-9606
SN  - 1089-7690
VL  - 156
IS  - 7
PB  - AIP Publishing
CY  - Melville
ER  -