X-ray photoelectron final-state screening in La(OH<span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mo>)</mo></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span>: A multiplet structural analysis

D. F. Mullica; C. K. C. Lok; H. O. Perkins; V. Young

doi:10.1103/PhysRevB.31.4039

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X-ray photoelectron final-state screening in La(OH $)_{3}$ : A multiplet structural analysis

D. F. Mullica, C. K. C. Lok, and H. O. Perkins

V. Young

Departments of Chemistry and Physics, Baylor University, Waco, Texas 76798

Department of Chemistry, Texas A&M University, College Station, Texas 77843

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Phys. Rev. B 31, 4039(R) – Published 15 March, 1985

DOI: https://doi.org/10.1103/PhysRevB.31.4039

Abstract

An investigation of the 3d, 4p, and 4d photoelectron spectra of La(OH $)_{3}$ is reported. The photoionization process creates final states I and II, a core hole and a core hole with a transfer of an electron from the ${OH}^{-}$ ligands to a ${La}^{4 +}$ 4f orbital, respectively. Spectroscopic evidence strongly suggests that final state I {( ${La}^{4 +}$ 3 $d^{1}$ 4 $f^{0}$ , ${9 O H}^{-}$ ), [ ${La}^{4 +}$ (4 $p_{3 / 2}$ $)^{1}$ 5 $d^{0}$ , ${9 O H}^{-}$ ], or ( ${La}^{4 +}$ 4 $d^{1}$ 4 $f^{0}$ , ${9 O H}^{-}$ )} is at a lower binding energy than final state II {( ${La}^{3 +}$ 3 $d^{1}$ 4 $f^{1}$ , ${9 O H}^{-}$ - $e^{-}$ ), [ ${La}^{3 +}$ (4 $p_{3 / 2}$ $)^{1}$ 5 $d^{1}$ , ${9 O H}^{-}$ - $e^{-}$ ], or ( ${La}^{3 +}$ 4 $d^{1}$ 4 $f^{1}$ , ${9 O H}^{-}$ - $e^{-}$ )}. The energy difference between final states I and II can be explained quite readily through the reconciliation of the interatomic secondary electron coexcitation theory (‘‘shake up’’) and the extra-atomic relaxation theory (‘‘shake down’’ or ‘‘well screened’’). Multiplet structures of the final state II related to the electron-hole exchange are clearly observed.

References (22)

H. Berthou, C. K. Jorgensen and C. Bonnelle, Chem. Phys. Lett. 38, 199 (1976).
P. Burroughs, A. Hamnett, A. F. Orchard and G. Thornton, J. Chem. Soc. Dalton Trans. 17, 1686 (1976).
S. Larsson, Chem. Phys. Lett. 32, 401 (1975).
G. Crecelius, G. K. Wertheim and D. N. E. Buchanan, Phys. Rev. B 18, 6519 (1978); G. K. Wertheim and M. Campagna, Solid State Commun. 26, 553 (1978).
J. C. Fuggle, M. Campagna, Z. Zolnierek and R. Lasser, Phys. Rev. Lett. 45, 1597 (1980); J. C. Fuggle, in X-Ray and Atomic Inner Shell Physics\(em1982, edited by B. Crasemann, AIP Conf. Proc. No. 94 (AIP, New York, 1982), pp. 661–675.
G. Wendin, Struct. Bonding (Berlin) 45, 1979. (a) The hole level is underlined in Wendin's work. We have adopted this notation. (b) Within the quasiparticle limit, the photoelectron spectral function of a core hole is a Voigt function that is a convolution of a Lorentzian and a Gaussian distribution. Usually, the lifetime of a core level is very long. The Lorentzian becomes a δ function so that the spectral function is a Gaussian. (c)This is a giant Coster-Kronig fluctuation.
W. O. Milligan, G. W. Beall, and D. F. Mullica, in Crystallography in North America (American Crystallographic Association, New York, 1983), p. 362, and references therein.
J. Weber, H. Berthou and C. K. Jorgensen, Chem. Phys. Lett. 45, 1 (1977). The maximum ligand field splitting is 0.62 eV.
It is not feasible to present all the materials in detail in this Rapid Communication. A forthcoming paper will present full coverage of all necessary materials.
J. M. Esteva, R. C. Karnatak, J. C. Fuggle and G. A. Sawatzky, Phys. Rev. Lett. 50, 910 (1983). Our experimental results of $ζ_{3 d}$ is 6.76 eV, which is in excellent agreement with their work. Our fitted intensity ratio ( ${3 d}_{5 / 2}$ : ${3 d}_{3 / 2}$ ) is 1.4.
D. W. Mardquardt, J. Soc. Ind. Appl. Math. 11, 431 (1963). Three parameters (amplitude, FWHM, and energy position) of each Gaussian peak and the parameters of a background function are all determined by the least-squares analysis.
J. A. D. Matthew, G. Strasser and F. P. Netzer, Phys. Rev. B 27, 5839 (1983). If the kinetic energy of the leaving electron is low, it may interact with the created electron-hole pair and make J != 1 states accessible to excitations which are attributed to the breakdown of the dipole selection rules.
J. Sugar, Phys. Rev. A 6, 1764 (1972). We have followed the procedure developed by Sugar. The ratios of $F^{k}$ and $G^{k}$ are the same as those in the article above. The optimized $G^{1}$ value is 4.67 and $F^{2}$ = 6.71, $F^{4}$ = 3.09, $G^{3}$ = 2.72, $G^{5}$ = 1.87, $ζ_{3 d}$ = 6.76, and $ζ_{4 f}$ = 0.08 (in eV units). The intensities of all the J = 1 terms are calculated by the dipole-type transition, and the intensities of the rest of J != 1 terms are simply multiplicities with the arbitrary scaling factor of 0.02.
Based on Wendin's work (see Ref. 6), the 4 p under " $"_{3 / 2}^{1}$ hole state cannot be interpreted in a one-electron framework, such as the Δ self-consistent-field method, because it is strongly influenced by the giant Coster-Kronig (GCK) process.
G. Strasser, F. P. Netzer and J. A. D. Matthew, Solid State Commun. 49, 817 (1984). The final state of 4p CEELS spectra of ${La}_{2}$ $O_{3}$ _ and ${CeO}_{2}$ _ is assigned to be (4 p under " $"_{3 / 2}$ $)^{1}$ ${5 d}^{1}$ , which is similar to the 4p "-" XPS final state II. The magnitude of the multiplet split of ${La}_{2}$ $O_{3}$ _ and ${CeO}_{2}$ _ estimated by the authors from their spectra is 1.6 eV.
S. Suzuki, T. Ishii and T. Sagawa, J. Phys. Soc. Jpn. 38, 156 (1975).
F. P. Netzer, G. Strasser and J. A. D. Matthew, Phys. Rev. Lett. 51, 211 (1983).
A. F. Starace, Phys. Rev. B 5, 1785 (1972).
S. Suzuki, T. Ishii and T. Sagawa, J. Phys. Soc. Jpn. 37, 1334 (1974). (a) They assumed that the interaction of ${4 d}^{1}$ and ${4 f}^{1}$ is very small and that the spin-orbit coupling of ${4 d}^{1}$ is large. (b) However, in view of the XAS and CEELS work (see Refs. 14–16), the ${4 d}^{1}$ interacts with ${4 f}^{1}$ very strongly. Therefore, the 4d distribution of XPS final state II ( ${La}^{3 +}$ 4 d under " $"^{1}$ ${4 f}^{1}$ , ~ 9 ${OH}^{-}$ "-" $e^{-}$ ) should resemble the 4d distribution of the CEELS final state and is assumed to be a skewed Gaussian. (c) In XAS and CEELS studies, the transition from the initial state ( ${La}^{3 +}$ ~ ${4 d}^{10}$ ${4 f}^{^0}$ , ~ $X^{-}$ ) to the final state ( ${La}^{3 +}$ ~ 4 d under " $"^{1}$ ${4 f}^{1}$ , ~ $X^{-}$ ) is not affected by the surrounding ligands because the electron transfer is an intra-atomic transition, where $X^{-}$ are halides. However, in a XPS process, the transition from the initial state ( ${La}^{3 +}$ ~ ${4 d}^{10}$ ${4 f}^{^0}$ , ~ $X^{-}$ ) to the final state II ( ${La}^{3 +}$ ~ 4 d under " $"^{1}$ ${4 f}^{1}$ , ~ $X^{-}$ "-" $e^{-}$ ) is strongly influenced by the surrounding ligands because the electron transfer is an interatomic transition. The existence of final state II depends solely on the probability of promoting an electron from the ligands to an empty 4f orbital.
J. Sugar, Phys. Rev. B 5, 1785 (1972); S. P. Kowalczyk, N. Edelstein, F. R. McFeely, L. Ley and D. A. Shirley, Chem. Phys. Lett. 29, 491 (1974). Our least-squares-fitted $ζ_{4 d}$ is 1.16 eV which is the same as the $ζ_{4 d}$ value of La metal in their work. Our fitted intensity ratio ( ${4 d}_{5 / 2}$ : ${4 d}_{3 / 2}$ ) is 1.5.
E. Wuilloud, B. Delley, W. D. Schneider and Y. Baer, Phys. Rev. Lett. 53, 202 (1984). The core-ionized state of ${La}^{3 +}$ is equivalent to ${Ce}^{4 +}$ . The empty 4f orbital and the conduction band, and the valence band of ${Ce}^{4 +}$ can be determined by bremsstrahlung isochromat spectroscopy and XPS, respectively. In their work, it is shown that the empty 4f orbital has a lower binding energy than the valence band.
D. D. Koelling, A. M. Boring and J. H. Wood, Solid State Commun. 47, 227 (1983).

[c1] H. Berthou, C. K. Jorgensen and C. Bonnelle, Chem. Phys. Lett. 38, 199 (1976).

[c2] P. Burroughs, A. Hamnett, A. F. Orchard and G. Thornton, J. Chem. Soc. Dalton Trans. 17, 1686 (1976).

[c3] S. Larsson, Chem. Phys. Lett. 32, 401 (1975).

[c4] G. Crecelius, G. K. Wertheim and D. N. E. Buchanan, Phys. Rev. B 18, 6519 (1978); G. K. Wertheim and M. Campagna, Solid State Commun. 26, 553 (1978).

[c5] J. C. Fuggle, M. Campagna, Z. Zolnierek and R. Lasser, Phys. Rev. Lett. 45, 1597 (1980); J. C. Fuggle, in X-Ray and Atomic Inner Shell Physics\(em1982, edited by B. Crasemann, AIP Conf. Proc. No. 94 (AIP, New York, 1982), pp. 661–675.

[c6] G. Wendin, Struct. Bonding (Berlin) 45, 1979. (a) The hole level is underlined in Wendin's work. We have adopted this notation. (b) Within the quasiparticle limit, the photoelectron spectral function of a core hole is a Voigt function that is a convolution of a Lorentzian and a Gaussian distribution. Usually, the lifetime of a core level is very long. The Lorentzian becomes a δ function so that the spectral function is a Gaussian. (c)This is a giant Coster-Kronig fluctuation.

[c7] W. O. Milligan, G. W. Beall, and D. F. Mullica, in Crystallography in North America (American Crystallographic Association, New York, 1983), p. 362, and references therein.

[c8] J. Weber, H. Berthou and C. K. Jorgensen, Chem. Phys. Lett. 45, 1 (1977). The maximum ligand field splitting is 0.62 eV.

[c9] It is not feasible to present all the materials in detail in this Rapid Communication. A forthcoming paper will present full coverage of all necessary materials.

[c10] J. M. Esteva, R. C. Karnatak, J. C. Fuggle and G. A. Sawatzky, Phys. Rev. Lett. 50, 910 (1983). Our experimental results of $ζ_{3 d}$ is 6.76 eV, which is in excellent agreement with their work. Our fitted intensity ratio ( ${3 d}_{5 / 2}$ : ${3 d}_{3 / 2}$ ) is 1.4.

[c11] D. W. Mardquardt, J. Soc. Ind. Appl. Math. 11, 431 (1963). Three parameters (amplitude, FWHM, and energy position) of each Gaussian peak and the parameters of a background function are all determined by the least-squares analysis.

[c12] J. A. D. Matthew, G. Strasser and F. P. Netzer, Phys. Rev. B 27, 5839 (1983). If the kinetic energy of the leaving electron is low, it may interact with the created electron-hole pair and make J != 1 states accessible to excitations which are attributed to the breakdown of the dipole selection rules.

[c13] J. Sugar, Phys. Rev. A 6, 1764 (1972). We have followed the procedure developed by Sugar. The ratios of $F^{k}$ and $G^{k}$ are the same as those in the article above. The optimized $G^{1}$ value is 4.67 and $F^{2}$ = 6.71, $F^{4}$ = 3.09, $G^{3}$ = 2.72, $G^{5}$ = 1.87, $ζ_{3 d}$ = 6.76, and $ζ_{4 f}$ = 0.08 (in eV units). The intensities of all the J = 1 terms are calculated by the dipole-type transition, and the intensities of the rest of J != 1 terms are simply multiplicities with the arbitrary scaling factor of 0.02.

[c14] Based on Wendin's work (see Ref. 6), the 4 p under " $"_{3 / 2}^{1}$ hole state cannot be interpreted in a one-electron framework, such as the Δ self-consistent-field method, because it is strongly influenced by the giant Coster-Kronig (GCK) process.

[c15] G. Strasser, F. P. Netzer and J. A. D. Matthew, Solid State Commun. 49, 817 (1984). The final state of 4p CEELS spectra of ${La}_{2}$ $O_{3}$ _ and ${CeO}_{2}$ _ is assigned to be (4 p under " $"_{3 / 2}$ $)^{1}$ ${5 d}^{1}$ , which is similar to the 4p "-" XPS final state II. The magnitude of the multiplet split of ${La}_{2}$ $O_{3}$ _ and ${CeO}_{2}$ _ estimated by the authors from their spectra is 1.6 eV.

[c16] S. Suzuki, T. Ishii and T. Sagawa, J. Phys. Soc. Jpn. 38, 156 (1975).

[c17] F. P. Netzer, G. Strasser and J. A. D. Matthew, Phys. Rev. Lett. 51, 211 (1983).

[c18] A. F. Starace, Phys. Rev. B 5, 1785 (1972).

[c19] S. Suzuki, T. Ishii and T. Sagawa, J. Phys. Soc. Jpn. 37, 1334 (1974). (a) They assumed that the interaction of ${4 d}^{1}$ and ${4 f}^{1}$ is very small and that the spin-orbit coupling of ${4 d}^{1}$ is large. (b) However, in view of the XAS and CEELS work (see Refs. 14–16), the ${4 d}^{1}$ interacts with ${4 f}^{1}$ very strongly. Therefore, the 4d distribution of XPS final state II ( ${La}^{3 +}$ 4 d under " $"^{1}$ ${4 f}^{1}$ , ~ 9 ${OH}^{-}$ "-" $e^{-}$ ) should resemble the 4d distribution of the CEELS final state and is assumed to be a skewed Gaussian. (c) In XAS and CEELS studies, the transition from the initial state ( ${La}^{3 +}$ ~ ${4 d}^{10}$ ${4 f}^{^0}$ , ~ $X^{-}$ ) to the final state ( ${La}^{3 +}$ ~ 4 d under " $"^{1}$ ${4 f}^{1}$ , ~ $X^{-}$ ) is not affected by the surrounding ligands because the electron transfer is an intra-atomic transition, where $X^{-}$ are halides. However, in a XPS process, the transition from the initial state ( ${La}^{3 +}$ ~ ${4 d}^{10}$ ${4 f}^{^0}$ , ~ $X^{-}$ ) to the final state II ( ${La}^{3 +}$ ~ 4 d under " $"^{1}$ ${4 f}^{1}$ , ~ $X^{-}$ "-" $e^{-}$ ) is strongly influenced by the surrounding ligands because the electron transfer is an interatomic transition. The existence of final state II depends solely on the probability of promoting an electron from the ligands to an empty 4f orbital.

[c20] J. Sugar, Phys. Rev. B 5, 1785 (1972); S. P. Kowalczyk, N. Edelstein, F. R. McFeely, L. Ley and D. A. Shirley, Chem. Phys. Lett. 29, 491 (1974). Our least-squares-fitted $ζ_{4 d}$ is 1.16 eV which is the same as the $ζ_{4 d}$ value of La metal in their work. Our fitted intensity ratio ( ${4 d}_{5 / 2}$ : ${4 d}_{3 / 2}$ ) is 1.5.

[c21] E. Wuilloud, B. Delley, W. D. Schneider and Y. Baer, Phys. Rev. Lett. 53, 202 (1984). The core-ionized state of ${La}^{3 +}$ is equivalent to ${Ce}^{4 +}$ . The empty 4f orbital and the conduction band, and the valence band of ${Ce}^{4 +}$ can be determined by bremsstrahlung isochromat spectroscopy and XPS, respectively. In their work, it is shown that the empty 4f orbital has a lower binding energy than the valence band.

[c22] D. D. Koelling, A. M. Boring and J. H. Wood, Solid State Commun. 47, 227 (1983).

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X-ray photoelectron final-state screening in La(OH $)_{3}$ : A multiplet structural analysis

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X-ray photoelectron final-state screening in La(OH)3: A multiplet structural analysis

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References (22)

X-ray photoelectron final-state screening in La(OH $)_{3}$ : A multiplet structural analysis