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Simulations of x-ray absorption spectra for CO desorbing from Ru(0001) with transition-potential and time-dependent density functional theory approaches

Authors :
Gabriel L. S. Rodrigues
Elias Diesen
Johannes Voss
Patrick Norman
Lars G. M. Pettersson
Source :
Structural Dynamics, Vol 9, Iss 1, Pp 014101-014101-11 (2022)
Publication Year :
2022
Publisher :
AIP Publishing LLC and ACA, 2022.

Abstract

The desorption of a carbon monoxide molecule from a Ru(0001) surface was studied by means of X-ray Absorption Spectra (XAS) computed with Transition Potential (TP-DFT) and Time Dependent (TD-DFT) DFT methods. By unraveling the evolution of the CO electronic structure upon desorption, we observed that at 2.3 Å from the surface, the CO molecule has already predominantly gas-phase character. While C 1s XAS is quite insensitive to changes in the C–O bond length, the O 1s excitation is very sensitive with the π* coming down in energy upon CO bond stretching, which competes with the increase in orbital energy due to the repulsive interaction with the metallic surface. We show in a systematic way that the TP-DFT method can describe the XAS rather well at the endpoints (chemisorbed and gas phase) but is affected by artificial charge transfer and/or incorrect spin treatment in the transition region in cases like CO, where there are low-lying π* orbitals and large exchange interactions between the core 1s and valence-acceptor π* orbitals. As an alternative, we demonstrate by comparing with experimental data that a linear response approach using TD-DFT employing common exchange-correlation functionals and finite-size clusters can yield a good description of the spectral evolution of the 1s → π* transition with correct spin and gas-to-chemisorbed chemical shifts in good agreement with experiment.

Subjects

Subjects :
Crystallography
QD901-999

Details

Language :
English
ISSN :
23297778
Volume :
9
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Structural Dynamics
Publication Type :
Academic Journal
Accession number :
edsdoj.b02c7f9d26304132ad8c6258aef103a8
Document Type :
article
Full Text :
https://doi.org/10.1063/4.0000135