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Padova - 05/04/07 A.A. 2006-2007 Opportunità in Chimica VILLAGE: Virtual Italian Laboratory for Large-scale Applications in a Geographically distribuited.

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Presentation on theme: "Padova - 05/04/07 A.A. 2006-2007 Opportunità in Chimica VILLAGE: Virtual Italian Laboratory for Large-scale Applications in a Geographically distribuited."— Presentation transcript:

1 Padova - 05/04/07 A.A Opportunità in Chimica VILLAGE: Virtual Italian Laboratory for Large-scale Applications in a Geographically distribuited Environment.

2 Padova - 05/04/07 A.A Opportunità in Chimica

3 Padova - 05/04/07 A.A Opportunità in Chimica The molecular cluster model coupled to Density Functional Theory. DV-X : Ellis et al. Chem. Phys. 1973, 2, 41, Ellis et al. J. Chem. Phys. 1976, 65, Dmol: Delley, B. J. Chem. Phys. 1990, 92, 508, Delley, B. J. Chem. Phys. 1991, 94, ADF:Baerends et al. J. Comput. Chem. 1992, 99, 84.

4 Padova - 05/04/07 A.A Opportunità in Chimica Covalency: noble gas configuration; Lewis structures; qualitative valence bond theory. organic chemistry crystal field; ligand field. inorganic chemistry Molecular Orbital Theories

5 Padova - 05/04/07 A.A Opportunità in Chimica Bonding is the degree of interaction between two atoms, which can be described by the amount of covalent mixing of their atomic orbital. Solomon et al. Acc. Chem Res. 2000, 33, 859 Covalency in a spectroscopic sense is related not only to metal-ligand orbital mixing ratios (the symmetry-restricted covalency) but also to the distortions of the metal orbitals upon bond formation (the central-field covalence)

6 Padova - 05/04/07 A.A Opportunità in Chimica Ligand K-edge X-ray absorption spectroscopy (XAS) is a new experimental probe of the covalency of a metal-ligand bond. The principal ligand K-edge XAS experiment and illustrative experimental data for [CuCl 4 ] 2- and [ZnCl 4 ] 2-.

7 Padova - 05/04/07 A.A Opportunità in Chimica Cl 1s * Ligand K-edge spectroscopy is a direct probe of the covalency of a metal-ligand bond. Orbital energy diagram showing the ligand pre-edge transition.

8 Padova - 05/04/07 A.A Opportunità in Chimica Comparison of the electric dipole intensity mechanisms for ligand K-edge transitions and optical charge transfer transitions.

9 Padova - 05/04/07 A.A Opportunità in Chimica M K-edge: electric dipole forbidden (but quadrupole allowed) 1s M nd M transitions M L-edge: electric dipole allowed 2p M nd M transitions L K-edge: electric dipole allowed 1s L np L transitions

10 Padova - 05/04/07 A.A Opportunità in Chimica Background: Spin-Orbit Energy Levels j = 3/2 j = 1/2 mj = 1/2 mj = 3/2 mj = –1/2 = 1 (p) mj = –3/2 mj = 1/2 mj = –1/2 mj = 1/2 mj = –1/2 Spin-Orbit = 0 (s) s = 1/2 Zeeman

11 Padova - 05/04/07 A.A Opportunità in Chimica Ti( 5 -C 5 H 5 )Cl 3 Ti( 5 -C 5 H 5 ) 2 Cl 2 TiCl 4 Application of SO-RTD-DFT to closed shell complexes

12 Padova - 05/04/07 A.A Opportunità in Chimica Ti K-edge of TiCl 4, TiCpCl 3, TiCp 2 Cl 2 Kuetgens & Hormes SIF Conference Proceedings 1990, 25, 59 DeBeer George et al. J. Am. Chem. Soc. 2005, 217, 667

13 Padova - 05/04/07 A.A Opportunità in Chimica Cl K-edge TiCl 4, TiCpCl 3, TiCp 2 Cl 2 Wen & Hitchcock Can. J. Chem. 1993, 71, 1632 Ti L 2,3 -edge TiCl 4, TiCpCl 3, TiCp 2 Cl 2 DeBeer George et al. J. Am. Chem. Soc. 2005, 217, 667

14 Padova - 05/04/07 A.A Opportunità in Chimica Background: Spin-Orbit Energy Levels j = 3/2 j = 1/2 mj = 1/2 mj = 3/2 mj = –1/2 = 1 (p) mj = –3/2 mj = 1/2 mj = –1/2 mj = 1/2 mj = –1/2 Spin-Orbit = 0 (s) s = 1/2 Zeeman

15 Padova - 05/04/07 A.A Opportunità in Chimica Correlation diagram of TiCl 4, TiCpCl 3, and TiCp 2 Cl 2 frontier orbitals

16 Padova - 05/04/07 A.A Opportunità in Chimica The relativistic two-component ZORA-TDDFT This method allows the calculation of excitation energies and intensities for closed shell molecules, including spin–orbit coupling and with full use of symmetry. F. Wang et al. J. Chem. Phys. 2005, 122,

17 Padova - 05/04/07 A.A Opportunità in Chimica ZORA-TDDFT 2 = corresponds to to square of the excitation energies The oscillator strength f can be exctracted from F

18 Padova - 05/04/07 A.A Opportunità in Chimica

19 Padova - 05/04/07 A.A Opportunità in Chimica

20 Padova - 05/04/07 A.A Opportunità in Chimica Cl K-edge TiCl 4, TiCpCl 3, TiCp 2 Cl 2 DeBeer George et al. J. Am. Chem. Soc. 2005, 217, 667

21 Padova - 05/04/07 A.A Opportunità in Chimica Ti L 2,3 -edge

22 Padova - 05/04/07 A.A Opportunità in Chimica M. Parrinello, Solid State Commun. 1997, 102, 107 FROM SILICON TO RNA: THE COMING OF AGE OF AB INITIO MOLECULAR DYNAMICS First principle quantum mechanical calculations are by now considered a sort of new spectroscopy, being widely recognized that the chemical and structural information they provide is often more accessible and likewise reliable than that provided by conventional spectroscopies

23 Padova - 05/04/07 A.A Opportunità in Chimica People want to change the natural into the useful unnatural into the useful unnatural Hoffmann, R. in the Introduction to The new chemistry Nina Hall ed. Cambridge University Press, 2000

24 Padova - 05/04/07 A.A Opportunità in Chimica Perturbations induced by dilute impurities in the electronic structure of a specific host Casarin et al J. Mol. Struct. (Theochem) 2003, 631, 11 Chem. Phys. Lett. 2004, 392, 146 Chem. Phys. Lett. 2005, 405, 459

25 Padova - 05/04/07 A.A Opportunità in Chimica Phenomena related to the coordination chemistry of surfaces Casarin et al J. Phys. Chem. B 2002, 106, 795 Inorg. Chem. 2003, 42, 436 Phys. Chem. Chem. Phys. 2003, 5, 2461 Surf. Sci. 2004, 566, 451 Surf. Sci. 2004, 566, 890 J. Phys. Chem. B 2005, 109, 1652 J. Phys. Chem. B 2005, 109, J. Phys. Chem. B 2005, 109, J. Phys. Chem. C submitted

26 Padova - 05/04/07 A.A Opportunità in Chimica Molecular Models of Extended Solids Casarin et al. Inorg. Chem. 2004, 43, 5865 Inorg. Chem. 2005, 44, 6225 Cryst. Growth Des. 2007, 7, xxx

27 Padova - 05/04/07 A.A Opportunità in Chimica Cl K-edge XAS spectra of [ZnCl 4 ] 2- and D 2d - [CuCl 4 ] 2- ; inset shows the d x 2 - y 2 HOMO of D 4h - [CuCl 4 ] 2-. Orbital energy diagram showing the ligand pre-edge transition. 1s 4p


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