Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces (2024)

Gavnholt, J., Olsen, T., Engelund, M. (2008). Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces. Physical Review B Condensed Matter, 78(7), 075441. https://doi.org/10.1103/PhysRevB.78.075441

Gavnholt, Jeppe ; Olsen, Thomas ; Engelund, Mads et al. / Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces. In: Physical Review B Condensed Matter. 2008 ; Vol. 78, No. 7. pp. 075441.

@article{057ce20a5c9f4f29961a46e0e46c9389,

title = "Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces",

abstract = "We present a modification of the Delta self-consistent field (Delta SCF) method of calculating energies of excited states in order to make it applicable to resonance calculations of molecules adsorbed on metal surfaces, where the molecular orbitals are highly hybridized. The Delta SCF approximation is a density-functional method closely resembling standard density-functional theory (DFT), the only difference being that in Delta SCF one or more electrons are placed in higher lying Kohn-Sham orbitals instead of placing all electrons in the lowest possible orbitals as one does when calculating the ground-state energy within standard DFT. We extend the Delta SCF method by allowing excited electrons to occupy orbitals which are linear combinations of Kohn-Sham orbitals. With this extra freedom it is possible to place charge locally on adsorbed molecules in the calculations, such that resonance energies can be estimated, which is not possible in traditional Delta SCF because of very delocalized Kohn-Sham orbitals. The method is applied to N2, CO, and NO adsorbed on different metallic surfaces and compared to ordinary Delta SCF without our modification, spatially constrained DFT, and inverse-photoemission spectroscopy measurements. This comparison shows that the modified Delta SCF method gives results in close agreement with experiment, significantly closer than the comparable methods. For N2 adsorbed on ruthenium (0001) we map out a two-dimensional part of the potential energy surfaces in the ground state and the 2 resonance. From this we conclude that an electron hitting the resonance can induce molecular motion, optimally with 1.5 eV transferred to atomic movement. Finally we present some performance test of the Delta SCF approach on gas-phase N2 and CO in order to compare the results to higher accuracy methods. Here we find that excitation energies are approximated with accuracy close to that of time-dependent density-functional theory. Especially we see very good agreement in the minimum shift of the potential energy surfaces in the excited state compared to the ground state.",

keywords = "STATES, SYSTEMS, ; AUGMENTED-WAVE METHOD, DENSITY-FUNCTIONAL THEORY, GREENS-FUNCTION, DESORPTION, ELECTRON-GAS, CO, INVERSE-PHOTOEMISSION, EXCITATION-ENERGIES",

author = "Jeppe Gavnholt and Thomas Olsen and Mads Engelund and Jakob Schi{\o}tz",

note = "Copyright 2008 American Physical Society",

year = "2008",

doi = "10.1103/PhysRevB.78.075441",

language = "English",

volume = "78",

pages = "075441",

journal = "Physical Review B Condensed Matter",

issn = "0163-1829",

publisher = "American Physical Society",

number = "7",

}

Gavnholt, J, Olsen, T, Engelund, M 2008, 'Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces', Physical Review B Condensed Matter, vol. 78, no. 7, pp. 075441. https://doi.org/10.1103/PhysRevB.78.075441

Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces. / Gavnholt, Jeppe; Olsen, Thomas; Engelund, Mads et al.
In: Physical Review B Condensed Matter, Vol. 78, No. 7, 2008, p. 075441.

Research output: Contribution to journal › Journal article › Research › peer-review

TY - JOUR

T1 - Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces

AU - Gavnholt, Jeppe

AU - Olsen, Thomas

AU - Engelund, Mads

AU - Schiøtz, Jakob

N1 - Copyright 2008 American Physical Society

PY - 2008

Y1 - 2008

N2 - We present a modification of the Delta self-consistent field (Delta SCF) method of calculating energies of excited states in order to make it applicable to resonance calculations of molecules adsorbed on metal surfaces, where the molecular orbitals are highly hybridized. The Delta SCF approximation is a density-functional method closely resembling standard density-functional theory (DFT), the only difference being that in Delta SCF one or more electrons are placed in higher lying Kohn-Sham orbitals instead of placing all electrons in the lowest possible orbitals as one does when calculating the ground-state energy within standard DFT. We extend the Delta SCF method by allowing excited electrons to occupy orbitals which are linear combinations of Kohn-Sham orbitals. With this extra freedom it is possible to place charge locally on adsorbed molecules in the calculations, such that resonance energies can be estimated, which is not possible in traditional Delta SCF because of very delocalized Kohn-Sham orbitals. The method is applied to N2, CO, and NO adsorbed on different metallic surfaces and compared to ordinary Delta SCF without our modification, spatially constrained DFT, and inverse-photoemission spectroscopy measurements. This comparison shows that the modified Delta SCF method gives results in close agreement with experiment, significantly closer than the comparable methods. For N2 adsorbed on ruthenium (0001) we map out a two-dimensional part of the potential energy surfaces in the ground state and the 2 resonance. From this we conclude that an electron hitting the resonance can induce molecular motion, optimally with 1.5 eV transferred to atomic movement. Finally we present some performance test of the Delta SCF approach on gas-phase N2 and CO in order to compare the results to higher accuracy methods. Here we find that excitation energies are approximated with accuracy close to that of time-dependent density-functional theory. Especially we see very good agreement in the minimum shift of the potential energy surfaces in the excited state compared to the ground state.

AB - We present a modification of the Delta self-consistent field (Delta SCF) method of calculating energies of excited states in order to make it applicable to resonance calculations of molecules adsorbed on metal surfaces, where the molecular orbitals are highly hybridized. The Delta SCF approximation is a density-functional method closely resembling standard density-functional theory (DFT), the only difference being that in Delta SCF one or more electrons are placed in higher lying Kohn-Sham orbitals instead of placing all electrons in the lowest possible orbitals as one does when calculating the ground-state energy within standard DFT. We extend the Delta SCF method by allowing excited electrons to occupy orbitals which are linear combinations of Kohn-Sham orbitals. With this extra freedom it is possible to place charge locally on adsorbed molecules in the calculations, such that resonance energies can be estimated, which is not possible in traditional Delta SCF because of very delocalized Kohn-Sham orbitals. The method is applied to N2, CO, and NO adsorbed on different metallic surfaces and compared to ordinary Delta SCF without our modification, spatially constrained DFT, and inverse-photoemission spectroscopy measurements. This comparison shows that the modified Delta SCF method gives results in close agreement with experiment, significantly closer than the comparable methods. For N2 adsorbed on ruthenium (0001) we map out a two-dimensional part of the potential energy surfaces in the ground state and the 2 resonance. From this we conclude that an electron hitting the resonance can induce molecular motion, optimally with 1.5 eV transferred to atomic movement. Finally we present some performance test of the Delta SCF approach on gas-phase N2 and CO in order to compare the results to higher accuracy methods. Here we find that excitation energies are approximated with accuracy close to that of time-dependent density-functional theory. Especially we see very good agreement in the minimum shift of the potential energy surfaces in the excited state compared to the ground state.

KW - STATES

KW - SYSTEMS

KW - ; AUGMENTED-WAVE METHOD

KW - DENSITY-FUNCTIONAL THEORY

KW - GREENS-FUNCTION

KW - DESORPTION

KW - ELECTRON-GAS

KW - CO

KW - INVERSE-PHOTOEMISSION

KW - EXCITATION-ENERGIES

U2 - 10.1103/PhysRevB.78.075441

DO - 10.1103/PhysRevB.78.075441

M3 - Journal article

SN - 0163-1829

VL - 78

SP - 075441

JO - Physical Review B Condensed Matter

JF - Physical Review B Condensed Matter

IS - 7

ER -

Gavnholt J, Olsen T, Engelund M, Schiøtz J. Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces. Physical Review B Condensed Matter. 2008;78(7):075441. doi: 10.1103/PhysRevB.78.075441