Slide1 :
Slide2 : e- e- e- e- Einstein Photoelectric Effect Ann. Phys. Leipzig 1905, 17, 132-148
Nobel Prize in Physics, 1921
Slide3 : e- e- e- Einstein Photoelectric Effect Ehv - Ee- = Ionization Energy hv e-
Slide4 : “The importance of ionization energy lies in the close correlation found between electron configuration (a microscopic property) and chemical behavior (a macroscopic property).
...The chemical properties of any atom or molecule are related to the configuration of the atom's or molecule’s valence electrons, and the stability of these electrons is reflected directly in the ... ionization energies.”
...provide well-defined, precise benchmarks for computational methods.
...are important quantities in thermodynamic cycles. (above from Raymond Chang, "General Chemistry") Why Ionization Energies?
Slide5 : AUFBAU PRINCIPLE
Electrons tend to occupy the most stable orbitals.
KOOPMANS’ THEOREM
Ionization energies correspond to orbital energies.
BOND PRINCIPLES
i.e. The sigma bond between two atoms is stronger than the pi bond.
ELECTRONEGATIVITY PRINCIPLES
i.e. Fluorine is highly electronegative and attracts electron density.
REACTIVITY PRINCIPLES
i.e. Protonation occurs at the atom with the most unstable electron density.
i.e. Chemical oxidation removes the electron from the highest occupied
orbital. Ionizations Provide Experimental Basis for Common Chemistry Principles
Slide6 : Fundamental Chemical Understanding 3. What is the energy profile of the process? The Molecular Structure View
Slide7 : Fundamental Chemical Understanding The Molecular Structure View 1. Where do atoms begin and where do they end? 2. What is the mechanism of the process? 3. What is the energy profile of the process? Reaction coordinate Energy The Electronic Structure View 1. Where do electrons begin and where do they end?
Slide8 : Chemistry is About Movement of Electrons Electrochemistry
Energy Storage
Energy Conversion
Biology
Slide9 : 2. Electron Transfer Processes:
[Cr(OH2)6] 2+ + [CoCl(NH3)5] 2+ Chemistry is About Movement of Electrons Molecular Electronics
Energy Conversion
Photochemistry
Biology
Slide10 : Chemistry is About Movement of Electrons 3. Bond Making / Bond Breaking Processes: C C H Br + Synthesis
Catalysis
Acid / Base Chemistry
Etc. Etc.
Slide11 : Chemistry is About Movement of Electrons 4. Electronic Transitions: Spectroscopy
Photochemistry
Optoelectronics
Photosynthesis
Slide12 : Core Ionizations are
Element Specific
..and Dependent Upon Environment
Slide13 : Photoelectron Spectroscopy
is a Huge Field: Search of J. Am. Chem. Soc. ASAP articles, current + four years for “photoelectron” yielded 444 articles!
Slide14 : Wide Range of Applications