Hungary-Croatia IPA Cross –border Co-operation Programme 2007-2013

1. Hungary-Croatia IPA Cross –border Co-operation Programme 2007-2013 Harmonization of Biotechnology BSc out-put with the Medical Biotechnology MSc in-put requirements at Osijek and Pecs Universities HUHR/1001/2.2.1/0010- BIOTECHEDU

2. PHYSICS – OSIJEK INTRODUCTION TO SPECTROSCOPY Dario Faj, Hrvoje Brkić

3. Structure of atoms - hystory review • Structure and stability of atoms and moleculas • Radioactivity. EM vawes • Interaction EM vawes and matter • Introduction to spectroscopy

4. 1. Structure of atoms - hystory review

5. Structure of nuclei Particle Symbol Mass EnergyCharge (kg) (MeV) ---------------------------------------------------------- Proton p 1.672*10-27 938.2 + Neutron n 1.675*10 -27 939.2 0 Electron e 0.911*10 -30 0.511 - • protonsand neutrons = nucleons • -Z number of positively charged protons (1.6 10-19 C) • -N number of neutral neutrons (no charge) • -A number of nucleons = mass number • Outside of nuclei • Z electrons (light negatively charged particles)

6. Identification of izotopes

7. ATOMatomoV • Demokritand Leukip 300 a.d. • R. Bošković – ADOPT CONCEPT OF ATOMS. • Dalton – define chemical element1800.g • R. Brown – existance of atom - experimental 1827 g. • D. Mendeleev – table of elements 1866 g. Structure • J.J.Thomson - electron 1897g., first model of atom • E. Rutherford – atomic nuclei ( solar system model of atom) • N. Bohr - model of hydrogen atom - postulat • A.Sommerfeld – aditional quantum numbers (ℓ, m)

8. Early models of atom Bohr + Sommerfeld

9. Wave nature of ectronsL. de Broglie • Atomic particles have wave characteristics also: • Difraction of electrons • E. Schrödinger - wave mehanics • Vawe function of electron ψ(r): • Solutions are energetic stations of electrons described with quantum numbers n, ℓ, m

10. Quantum numbers • n - main: discrete energy of electrons in electric field of nuclei; energetic shells: K,L,M,N..; number of electrons in a shell is 2n2 • l - orbital: orbitals: s,p,d..; can be 0, 1, ... n-1 • m– magnetic: can be from – l to l • ms – spin can be +1/2 and -1/2 • Pauli exclusion principle

11. Today

12. 2. Structure and stability of atoms and moleculas

13. ELECTRON CONFIGURATION • the distribution of electrons of an atom or molecule (or otherphysical structure) in atomic or molecular orbitals • an energy is associated with each electron configuration • upon certain conditions, electrons are able to move from one orbital to another by emission or absorption of a quantum of energy, in the form of a electromagnetic wave (photon)

14. Electron configuration II • For example Germanium (32e-) has electron configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 2p2 Image shows the order of filling atomical orbitales for atoms

16. Electron configuration III • knowledge of the electron configuration of different atoms is useful in understanding the structure of the periodic table of elements • the concept is also useful for describing the chemical bonds that hold atoms together.

17. MOLECULES • stabile assotiations of atoms • structure tending to minimal potential energy

18. Molecular bonds • Covalent • Ionic (exteme covalent) • Polar – part of molecula is more electronegative and electron cloud is shifted to this side - electric dipol P=δl

19. Energy of moleculas • Always smaller than total energy of free atoms (principle of minimum energy) Energy change electronic vibration rotation Between Between Between molecular orbitals vibration stations rotation stations

20. Rotationsof two-atoms-molecula Rotational quantum numberj atom 1 atom 2 ~ 0,005 eV Energy difference between neighbour states depends ofj

21. Vibrations of two-atom-moleculas Vibration quantum numbern atom 1 atom 2 ~ 0.1 eV Energy difference between neighbour states is constant

22. 3. Radioactivity. EM vawes Henri Becquerel 1852-1908Maria Curie 1867-1934

23. Stability of nucleus To many neutrons To many protons

24. Radioactive decay • Simple calculator for number of non decayed nucleus Process by which an atomic nucleus of unstable atom loses energy by emitting energy as particles or EM vawes Number of particles which will remain after some time period is described by equation

25. Electromagneticwave

26. EM spectra Energy ofEM vawe E = h n = hc/l

27. Dual nature of EM vawes • Example: visible light as particles (photons)-photoefect: • Vawe nature of light – difraction • Exercise - how to calculate the wavelength of light

28. 4. Interaction of EM vawes and matter

29. Some of the interacions: Coherent scattering (Rayleigh scattering) Compton scaterring Pair production Photoelectrical efect The nature of interaction depends of wave lenght of EM vawes and passing material atomic number

30. Coherent scattering(Rayleigh scattering) + + +

31. Compton scattering + + +

32. Photoelectric effect + + + X-photon

33. Pair production Positron (+) Photon energy = 1.022 MeV 511 keV 511 keV Electron (-)

34. Atenuation and absorption Geometry of narrow EM beam

35. Beer Lambert law HVL: half value layer – poludebljina apsorpcije TVL: tenth value layer – deset debljina apsorpcije Beer Lambert law gives relation between intensity (I) transmitted by the layer with thickness (x) and incident intensity (I0) Simple calculator for Beer Lambert law

36. HVL

37. 5. Introduction to spectroscopy

38. Spectroscopy • Interaction of EM wave and atoms or moleculas • No chemical effects • result: spectar • Change energy of the system and gives informations of structure and function of system

39. According to interaction: Emission • relacsation of eksicited moleculas • luminiscence Absorption • spectar transmited vawe after passing the matter Interferention • interferention of scattered vawes on structures

40. According to EM vawe energy • Radiofrequent –between magnetic spin states – NMR • Microvawe – between rotational energy states in moleculas with dipole momentum • Infrared – vibration energy states of moleculas • Visible and UV – between electron energies of valence electrons • X-rays – between inner shells of atoms RTG structural analysis

41. Instruments in spectroscopy • Schematic layout for prism or grating spectrometers is shown in figure • It consists from slit (S), colimating lens (L1), disperser (prism or a grating) camera lens (L2) and detector (P)

42. Prism instruments • Limit resolwing power is in order of 30 000 • It covers region between 2.5 μm and 350 nm • Advantages – relatively cheap and simple to adjust • Disadvantage – low dispersion and resolwing power

43. Grating instruments • Usual gratings have 600 or 1200 lines/mm • Maximum resolving power is in order of 500 000 • Maximum wavelength for which a given grating can be used is by λ<2d • This means that in infrared region corser rullings are used

44. Interferometric spectrometers • Two most usual types: Faby-Perot and Michleson interferometer • Faby-Perot has a multiple reflections between two mirrors (F-region) with partialy reflecting coatings – interference image is created

45. Interferometric spectrometers • Michleson interferometer – modification od standard Michleson interferometer – mirror M2 is moved during the scan, so it can collect all the vavelenghts from the source The image is created in the plane P after passing (reflecting) trough beamsplitter (B) and reflecting in a mirrors M1 and M2

46. Interferometric spectrometers • Michleson interferometer has extensive usage in Fourier Transform Spectroscopy • Resolution depends only on the path difference that mirror M2 passes • It can easily achieve resolution of order 1 000 000