Chemistry

Introduction. Photoelectric effect. The photoemission spectrum. Outline of photoemission theory. Transition probability. Transition matrix element for core levels. "Frozen orbital" approximation. Koopmans theorem and implications. Photoemission from the valence levels in a crystal (outline). 3-step, single-step model. Deviations from Koopmans Theorem, examples of photoelectronic spectra from atomic systems with evidence of configuration interaction in the initial state: Cs- ion. Spectrum of the He. Review of the Russell-Saunders rules for the attribution of atomic term symbols, examples and determination of the ground state. Atomic oxygen spectrum. Electronic states in diatomic molecules. Symmetry considerations. Determination of the ground state and of the various ionized states in O2, N2, CO, NO. Notes on the B2 molecule. Vibrational fine structure in the spectra of diatomic molecules. Franck-Condon principle. Character determination of orbitals. UPS and XPS spectra of N2, CO, O2, NO. Autoionization in O2. Spin-orbit coupling. UPS spectra of hydrogen halides, diatomic halogens. UPS ICl and IBr spectra. UPS spectra of polyatomic molecules: H2O, NH3 and CH4. H2O XPS spectrum. Asymmetry in C 1s of CH4. Jahn-Teller effect in NH3 and CH4. UPS spectra of acetylene, benzene, carbonyl compounds: Cr (CO) 6, W (CO) 6. Influence of the relativistic effect on the ionization energy. Compounds XRe (CO) 5, variation of the character of HOMO as the halogen varies. UPS spectrum of BF3. Sequence of boron halides. Sequence of bromomethanes and fluoromethanes. JT effect, SO coupling, halogen electronegativity effect, life time of the ionized state, extension of the vibrational progression. UPS spectra of ferrocene and substituted ferrocenes: ethyl-FC, vinyl-Fc, ethinyl-Fc. The photoionization cross section. Z dependence, hv dependence. Delayed maxima and Cooper minima. Examples in the valence of Pd and Ni organometallic compounds. Character of the HOMO based on the variation of the cross section. Introduction to Shake-up satellites. Sudden and adiabatic approximation. Multiplet splitting due to core-valence exchange interactions. Determination of the nature of the ionized ground state based on the extent of the exchange interaction. Multiplet splitting due to core-valence exchange interactions. Examples of Mn 2s, 3s and 3p regions in Mn (II) compounds. Identification of the oxidation state of Mn based on the extent of coupling in the 3s region, for example oxides and mixed oxides of Mn. Configuration interaction satellites in the final state. eg halides Rb and K. Example compounds Mn (II). System energetics with charge transfer satellites. Copper (II) halides. Two-hole Kotani-Toyozawa model, screening process in the case of metals and insulators. Asada-Sugano LCAO-MO approach for decoupled and coupled ions. Sawatzky approach in the description of the electronic structure of copper and cobalt dihalides. Hole-doping in copper-based superconductors. Non-local screening in NiO, Ni2p region. Electrical characteristics in compounds of transition metals, Mott insulators and charge transfer semiconductors. Electronic valence structure of NiO. Resonant and satellite photoemission. General principles of the Auger effect. Description of the NiO Auger L3VV signal and nature of the valence satellite. Reverse photoemission and BIS spectroscopy. Optical gap in NiO. NiO vs. NiS, band structure. Genuine Mott Compounds. SrTiO3. Broadening of the signal due to the life time of the hole. Coster-Krönig and Super Coster-Krönig processes. Auger parameter changed. Auger spectra of copper. L3M45M45 signal analysis. Auger-photoemission coincidence spectra, composition of the L2 signal. Cu2p and Auger spectra of copper (I) and (II) compounds. Satellite. Surface sensitivity in photoemission. Universal Curve of the IMFP. Electronic inelastic mean free path. Modes for varying the surface sensitivity in photoemission. Energy variation of the incident photon. Change in take-off angle. Examples. Sputtering. Introduction to Chemical Shift. Definition of binding energy. Corrections and simple model for Chemical Shift. Examples. Historical example on the chemical shift: the "ESCA molecule" ethyl trifluoroacetate. Original study and new interpretation. Contributions to line width widening. Effect of conformation. Semi-quantitative analysis in XPS. Surface-molecule interaction. Surface reconstruction in Si (100). XPS spectrum. Adsorption of methanol on Si (100). XPS spectra. Adsorption of methanol on Si (100) and Si (111). Valence and core spectra. Adsorption of ethylene on Si (100). UPS of crystalline solids. Conservation of the moment (wave vector), approximations. Angular distribution of the photocurrent. Band structure and E vs. k curves (hints). CO deposition on metals. Chemisorption and physisorption. Angle-resolved photoemission. spectrum of CO chemisorbed on Ni. Effect of photon polarization and symmetry criteria. CO-metal surface bond. Polar and azimuth angle dependence. Blyholder model. Example of the CO / Ni (110) (2x1) p2mg chemisorbed system. Band structure. Physisorption of CO. Example of the CO / Ag system (111). Geometry of adsorption and dispersion of the sigma bands. Chemisorption N2 on Fe (111). Alpha and gamma phase. UPS spectra with different polarization. XPS spectra. Laboratory: X-ray sources, characteristics, monochromators, satellites, resolution. Analyzer, pass energy. Photomultiplier. Electrostatic charging of the sample. Compensation. Vacuum meters. Pirani vacuum gauge. Bayard-Alpert vacuum gauge. Penning vacuum gauge. Vacuum pumps: rotary pump. Turbomolecular pump. Diffusion pump. Sublimation pump (getter). Ionic pump. Cryopump. XPS data processing: curve-fitting. Shirley background, linear. Model curves for the line shape: Voigt, Pseudo-voigt, asymmetry, Doniach-Sunjic. Laboratory experiences: Preparation of a copper surface passivated with 4-acetamidothiophenol + XPS measurement + XPS measurement data processing. Si (111) surface preparation hydrogenated and functionalized with vinylferrocene + XPS measurement + XPS measurement data processing.

Knowledge of structure and reactivity of inorganic compounds from the courses of Inorganic Chemistry of the three-year degree. Basic knowledge of quantum mechanics, group theory and spectroscopy.

- "Photoelectron Spectroscopy, Principles and Applications" - Stefan Huefner - Third Edition - Springer

The course is held in the classroom with the help of powerpoint slides that are also shared on Google Meet for those who follow remotely.

Optional but strongly recommended attendance, especially in the classroom. Laboratory exercises are mandatory to take the exam.

The evaluation takes place through an oral examination of the skills acquired by the student. The topic of the interview concerns the program carried out in the classroom and the laboratory exercises. To take the oral exam it is necessary to have followed the laboratory exercises.

"Handbook of X-ray and ultraviolet photoelectron spectroscopy" - Briggs - Ed. Heiden (Chapter 1: "Basic Principles of Photoelectron Spectroscopy" - A.F. Orchard)

Lectures in the classroom with the help of powerpoint slide