Ionized and excited states of ferrocene: Symmetry adapted cluster–configuration–interaction study

The ground state, singlet, and triplet excited states, and ionized states of ferrocene Fe(C5H5)2 were studied by the symmetry adapted cluster (SAC)/SAC–configuration–interaction method. The calculated ionization energies and intensities fairly well reproduced the observed photoelectron spectrum in the wide region of 6–14 eV. In particular, the first two peaks (2E2′ and 2A1′) were assigned to the ionizations from the occupied 3d orbitals of Fe, mixed already with the two-electron shake-up processes. This is the first ab initio quantitative assignment that is consistent with the experimental data. For the singlet states, three d–d transitions were calculated at 2.12, 2.26, and 4.02 eV, which correspond to the experimental peaks observed at 2.69, 2.97, and 3.82 eV. We propose possible assignments for other absorption bands in the range of 2.12–6.57 eV. In another three triplet d–d transition states we calculated, we found that the energy order of these states (1 3E1″, 1 3E2″, 2 3E1″) differs from that of sin...

[1]  R. Hoffmann,et al.  Structure and chemistry of bis(cyclopentadienyl)-MLn complexes , 1976 .

[2]  Harry B. Gray,et al.  Electronic structure of metallocenes , 1971 .

[3]  H. Schaefer.  Methods of Electronic Structure Theory , 1977 .

[4]  T. J. KEALY,et al.  A New Type of Organo-Iron Compound , 1951, Nature.

[5]  A. Veillard,et al.  Ionization potentials of ferrocene and Koopmans' theorem. Anab initio LCAO-MO-SCF calculation , 1972 .

[6]  H. Koch,et al.  Coupled-cluster calculations on ferrocene and its protonated derivatives: Towards the final word on the mechanism of protonation of ferrocene? , 2000 .

[7]  Michael C. Zerner,et al.  An intermediate neglect of differential overlap technique for spectroscopy of transition-metal complexes. Ferrocene , 1980 .

[8]  Sean P. McGlynn,et al.  Electronic Absorption Spectrum of Ferrocene , 1967 .

[9]  W. Niessen,et al.  Many-body calculation of the valence photoemission spectrum of ferrocene , 1991 .

[10]  Jennifer C. Green,et al.  Gas phase photoelectron spectra of d- and f-block organometallic compounds , 1981 .

[11]  D. Scott,et al.  Erratum: Comprehensive Investigation of the Electronic Spectroscopy and Theoretical Treatments of Ferrocene and Nickelocene , 1961 .

[12]  A. Haaland.  Molecular structure and bonding in the 3d metallocenes , 1979 .

[13]  L. Karlsson,et al.  Electron Spectroscopy of Open‐Shell Systems: Spectra of Ni(C5H5)2, Fe(C5H5)2, Mn(C5H5)2, and Cr(C5H5)2 , 1972 .

[14]  H. Nakatsuji,et al.  Theoretical study on the ground and excited states of the chromate anion CrO2−4 , 1994 .

[15]  N. Rösch,et al.  An SCF Xα scattered-wave calculation for ferrocene , 1974 .

[16]  Malcolm L. H. Green,et al.  Electronic structure of metal complexes containing π-cyclopentadienyl and related ligands. Part 1.—He(I) photoelectron spectra of some closed-shell metallocenes , 1972 .

[17]  Manuela Merchán,et al.  Density matrix averaged atomic natural orbital (ANO) basis sets for correlated molecular wave functions , 1995 .

[18]  H. Nakatsuji,et al.  Theoretical study of the visible and ultraviolet spectra of chromyl chloride (CrO2Cl2) , 1993 .

[19]  P. Bagus,et al.  A theoretical study of the electronic structure of ferrocene and ferricinium: Application to Mössbauer isomer shifts, ionization potentials, and conformation , 1976 .

[20]  T. H. Dunning.  Gaussian Basis Functions for Use in Molecular Calculations. III. Contraction of (10s6p) Atomic Basis Sets for the First‐Row Atoms , 1970 .

[21]  Hiroshi Nakatsuji,et al.  Cluster expansion of the wavefunction, valence and rydberg excitations, ionizations, and inner-valence ionizations of CO2 and N2O studied by the sac and sac CI theories , 1983 .

[22]  A. Veillard,et al.  Excited states and electronic spectrum of ferrocene , 1974 .

[23]  P. Jeffrey Hay,et al.  Gaussian basis sets for molecular calculations. The representation of 3d orbitals in transition‐metal atoms , 1977 .

[24]  J. J. Smith,et al.  Absorption and Phosphorescence Spectrum of Matrix‐Isolated Ferrocene , 1968 .

[25]  H. Nakatsuji,et al.  Theoretical study on the excitation spectrum and the photofragmentation reaction of Ni(CO)4 , 1995 .

[26]  Kimihiko Hirao,et al.  Cluster expansion of the wavefunction. Symmetry-adapted-cluster expansion, its variational determination, and extension of open-shell orbital theory , 1978 .

[27]  E. Baerends,et al.  Level ordering in ferrocence. A comparision between the hartree-fock-slater and hartree-fock models , 1973 .

[28]  Hiroshi Nakatsuji,et al.  Cluster expansion of the wavefunction. Calculation of electron correlations in ground and excited states by SAC and SAC CI theories , 1979 .

[29]  J. Brunvoll,et al.  Molecular structures of dicyclopentadienylmagnesium and dicyclopentadienylchromium by gas-phase electron diffraction , 1974 .