The Jahn-Teller effect in the photoelectron spectrum of iron pentacarbonyl

John L. Hubbard, Dennis L Lichtenberger

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

High quality photoelectron spectra of gaseous Fe(CO)5 excited by HeI, HeII, and ArI photons have been obtained. Major attention is focused on the primarily metal 3d ionizations, which occur in the binding energy region from 7 to 11 eV. Ionization to the 2E′ positive ion state (centered at 8.6 eV) clearly shows the effects of Jahn-Teller distortions in the positive ion. This ionization results in two ionization bands of approximately equal intensity and shape separated by 0.38 eV at room temperature. These bands broaden and the splitting increases to 0.47 eV at 473 °K. Ionization to the 2E″ positive ion state, centered at 9.9 eV, is much less influenced by the Jahn-Tellar effect. There is no discernable splitting of this band at room temperature. These observations are discussed in terms of the electronic structure and bonding of Fe(CO)5. Simple model calculations of the energies of the doubly degenerate electronic states in relation to the appropriate doubly degenerate normal vibrational modes are used to investigate the splitting. The magnitudes of the 2E′ and 2E″ splittings are reproduced very well, and the temperature dependence is reproduced within experimental error. It is found that the vibrational motion primarily responsible for the splitting is a low frequency OC-Fe-CO bending in the equatorial plane. This bending is found in two normal modes, one of which is closely related to the Berry pseudorotation process. The splitting of the 2E′ ionization is clear experimental evidence in the gas phase that the preferred geometry of d7 M(CO)5 is not D3h in this case.

Original languageEnglish (US)
Pages (from-to)2560-2568
Number of pages9
JournalThe Journal of Chemical Physics
Volume75
Issue number6
StatePublished - 1981

Fingerprint

Jahn-Teller effect
Photoelectrons
Ionization
photoelectrons
iron
ionization
positive ions
Positive ions
Carbon Monoxide
Electronic states
room temperature
Binding energy
Temperature
Electronic structure
iron pentacarbonyl
vibration mode
Photons
binding energy
Gases
Metals

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

The Jahn-Teller effect in the photoelectron spectrum of iron pentacarbonyl. / Hubbard, John L.; Lichtenberger, Dennis L.

In: The Journal of Chemical Physics, Vol. 75, No. 6, 1981, p. 2560-2568.

Research output: Contribution to journalArticle

@article{63c5996a89424301a7f7c392f71d155a,
title = "The Jahn-Teller effect in the photoelectron spectrum of iron pentacarbonyl",
abstract = "High quality photoelectron spectra of gaseous Fe(CO)5 excited by HeI, HeII, and ArI photons have been obtained. Major attention is focused on the primarily metal 3d ionizations, which occur in the binding energy region from 7 to 11 eV. Ionization to the 2E′ positive ion state (centered at 8.6 eV) clearly shows the effects of Jahn-Teller distortions in the positive ion. This ionization results in two ionization bands of approximately equal intensity and shape separated by 0.38 eV at room temperature. These bands broaden and the splitting increases to 0.47 eV at 473 °K. Ionization to the 2E″ positive ion state, centered at 9.9 eV, is much less influenced by the Jahn-Tellar effect. There is no discernable splitting of this band at room temperature. These observations are discussed in terms of the electronic structure and bonding of Fe(CO)5. Simple model calculations of the energies of the doubly degenerate electronic states in relation to the appropriate doubly degenerate normal vibrational modes are used to investigate the splitting. The magnitudes of the 2E′ and 2E″ splittings are reproduced very well, and the temperature dependence is reproduced within experimental error. It is found that the vibrational motion primarily responsible for the splitting is a low frequency OC-Fe-CO bending in the equatorial plane. This bending is found in two normal modes, one of which is closely related to the Berry pseudorotation process. The splitting of the 2E′ ionization is clear experimental evidence in the gas phase that the preferred geometry of d7 M(CO)5 is not D3h in this case.",
author = "Hubbard, {John L.} and Lichtenberger, {Dennis L}",
year = "1981",
language = "English (US)",
volume = "75",
pages = "2560--2568",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "6",

}

TY - JOUR

T1 - The Jahn-Teller effect in the photoelectron spectrum of iron pentacarbonyl

AU - Hubbard, John L.

AU - Lichtenberger, Dennis L

PY - 1981

Y1 - 1981

N2 - High quality photoelectron spectra of gaseous Fe(CO)5 excited by HeI, HeII, and ArI photons have been obtained. Major attention is focused on the primarily metal 3d ionizations, which occur in the binding energy region from 7 to 11 eV. Ionization to the 2E′ positive ion state (centered at 8.6 eV) clearly shows the effects of Jahn-Teller distortions in the positive ion. This ionization results in two ionization bands of approximately equal intensity and shape separated by 0.38 eV at room temperature. These bands broaden and the splitting increases to 0.47 eV at 473 °K. Ionization to the 2E″ positive ion state, centered at 9.9 eV, is much less influenced by the Jahn-Tellar effect. There is no discernable splitting of this band at room temperature. These observations are discussed in terms of the electronic structure and bonding of Fe(CO)5. Simple model calculations of the energies of the doubly degenerate electronic states in relation to the appropriate doubly degenerate normal vibrational modes are used to investigate the splitting. The magnitudes of the 2E′ and 2E″ splittings are reproduced very well, and the temperature dependence is reproduced within experimental error. It is found that the vibrational motion primarily responsible for the splitting is a low frequency OC-Fe-CO bending in the equatorial plane. This bending is found in two normal modes, one of which is closely related to the Berry pseudorotation process. The splitting of the 2E′ ionization is clear experimental evidence in the gas phase that the preferred geometry of d7 M(CO)5 is not D3h in this case.

AB - High quality photoelectron spectra of gaseous Fe(CO)5 excited by HeI, HeII, and ArI photons have been obtained. Major attention is focused on the primarily metal 3d ionizations, which occur in the binding energy region from 7 to 11 eV. Ionization to the 2E′ positive ion state (centered at 8.6 eV) clearly shows the effects of Jahn-Teller distortions in the positive ion. This ionization results in two ionization bands of approximately equal intensity and shape separated by 0.38 eV at room temperature. These bands broaden and the splitting increases to 0.47 eV at 473 °K. Ionization to the 2E″ positive ion state, centered at 9.9 eV, is much less influenced by the Jahn-Tellar effect. There is no discernable splitting of this band at room temperature. These observations are discussed in terms of the electronic structure and bonding of Fe(CO)5. Simple model calculations of the energies of the doubly degenerate electronic states in relation to the appropriate doubly degenerate normal vibrational modes are used to investigate the splitting. The magnitudes of the 2E′ and 2E″ splittings are reproduced very well, and the temperature dependence is reproduced within experimental error. It is found that the vibrational motion primarily responsible for the splitting is a low frequency OC-Fe-CO bending in the equatorial plane. This bending is found in two normal modes, one of which is closely related to the Berry pseudorotation process. The splitting of the 2E′ ionization is clear experimental evidence in the gas phase that the preferred geometry of d7 M(CO)5 is not D3h in this case.

UR - http://www.scopus.com/inward/record.url?scp=0000287724&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000287724&partnerID=8YFLogxK

M3 - Article

VL - 75

SP - 2560

EP - 2568

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 6

ER -