I. General Introduction to Spectroscopy

1. I.     General Introduction to Spectroscopy II.        Absorption Spectroscopies --- UV-Vis, IR, Raman III.        Photon Electron Spectroscopy --- XPS, UPS IV.        X-ray Absorption Spectroscopy --- XANES, EXAFS V.          X-ray Crystallography VI.         Magnetic Properties VII.        Magnetic Resonance Spectroscopies Ph.D. students need to turn in Final written reports on a topic concerning a series of researches using one of the mentioned instruments. The topic and the titles of the main papers should be turned in before April 26.

2. X-Ray Absorption X-Ray Emission Photoelectron Emission Auger Electron Emission Fig.3 (a) Contributions to x-ray absorption. (After Henery, N.F.M., Lipson, H., and Weoster, W.A., “The Interpretation of X-ray Diffraction Photographs”. Macmillan, London, 1951.) (b) Various emission processes which give rise to spectroscopic analytical tools. Energy levels are shown schematically for atoms bound in a solid. (Adapted from Jenkins, R., “An Introduction to X-ray Spectroscopy”. Heyden, New York, 1974)

3. Interaction Between X-ray and material Incident beam (x-ray) absorbing substance Fluorescent x-rays heat Transmitted beam electrons scattered x-rays Compton recoil pohotoelectrons Unmodified electrons (coherent) Compton modified Auger electrons (incoherent)

4.  l  1； j  0 or 1 Table 6-3 Allowed combinations of quantum numbers Ag Fig. 6-20 Energy-level diagram of a silver atom with the allowed transitions indicated by arrows. (The line are labeled after a convention proposed by Siegbahn, except that K is used in place of K2.)

5. Transmitted x-ray photons The photoionization process

6. X-ray absorption / Emission spectroscopy

7. Characterization • X-ray Absorption Spectroscopy • X-ray Absorption Near Edge Spectroscopy (XANES) • Provides information on chemical states • Oxidation state • Density of states • Extended X-ray Absorption Fine Structure (EXAFS) • Provides local (~10 Å) structural parameters • Nearest Neighbors (coordination numbers) • Bond distances • Disorder

8. Absorption Photon Energy X-ray Absorption Spectroscopy • Absorption coefficient (m) vs. incident photon energy • The photoelectric absorption decreases with increasing energy • “Jumps” correspond to excitation of core electrons Adapted from Teo, B. K. EXAFS: Basic Principles and Data Analysis; Springer-Verlag: New York, 1986.

9. K 78.395 LI 13.88 LII 13.273 LIII 11.564 MI 3.296 MII 3.027 MIII 2.551 MIV 2.202 MV 2.122 NI 0.725 NII 0.609 NIII 0.519 Pt Fig. 1. X-ray absorption spectrum of metallic platinum at 100 K in the region of the L-absorption edges.

11. XAS

12. X-ray absorption from a local structure XANES/ EXAFS EXAFS現象與物理機制 Probability of X-ray Absorption:

13. Fig. 1 K-edge x-ray absorption spectra of iron in K3Fe(CN)6 and K4Fe(CN)6. The relative absorption with respect to the high-energy continuum background,αA is plotted.

14. XANES 譜峰例：鉻與銅化合物 Absorption coefficient XANES 包含電子信息（化學鍵）（a）中心原子價化 (b) 中心原子配位幾何 EXAFS 含中心原子結構

15. Cr(bpb)N ………post-edge background 定法是用一直線適配吸收邊緣前端約200eV至50eV之區間內吸收係數的變化趨勢，再將此適配的背景外插至吸收光譜終點 ………pre-edge background 定法是用多段式的三次多項式加以近似之，在各段的相接點處需滿足含數值及一階微分值皆為連續的要求 • Cr (bpb)粉末樣品在Cr K-邊緣處之X光吸收全譜圖 • 經過背景扣除及正規化處理後所得之XANES

16. Energy (eV) 各種氧化態之錳金屬粉樣品在Mn K-邊緣處之XANES

17. Ti4+在各類鈦化合物之XANES

18. X-Ray Absorption Near Edge Spectroscopy (XANES) XANES measurements for reduced 10%, 40%, 60% Pt/C, and Pt foil at 200, 300, 473 and 673 K. A total of 16 measurements are shown. All overlay well with bulk Pt (Pt foil); therefore, the samples are reduced to their metallic state.

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20. 銅K吸收邊緣之吸收能譜受單光解析度之影響情況，實線之解析度為2eV，虛線為5eV，折線為9eV銅K吸收邊緣之吸收能譜受單光解析度之影響情況，實線之解析度為2eV，虛線為5eV，折線為9eV

21. EXAFS APPARATUS FLUORESCENCE EXAFS