Faculdade de Ciências e Tecnologia

Spectroscopic Techniques

Code

11518

Academic unit

Faculdade de Ciências e Tecnologia

Department

Departamento de Física

Credits

3.0

Teacher in charge

António Alberto Dias, Maria Luisa Dias de Carvalho de Sousa Leonardo

Weekly hours

2

Total hours

28

Teaching language

Português

Objectives

By accomplishing this CU the students will have developed scientific knowledge and know-how in order to:

•          Undertake informed decisions on which spectroscopic technique is suitable for the resolution of a given challenge, in order to investigate the fundamental properties of a particular material.

•          Adequately process the retrieved spectral data and carry out spectral interpretation

•          Interpret the obtained results taking into account the basic principles of Atomic and Molecular Physics in order to identify the origin of the observed transitions and energy levels involved; Interpret the shape and intensity of the observed signal and gather information relevant to the problem in hands.

Prerequisites

It is highly recommended the previous approval in the following courses: Ótica, Física Atómica (e Física Molecular) e Mecânica Quântica.

Subject matter

  1. Introduction

Brief historical perspective; Considerations on Optics, Atomic (and Molecular) physics and Quantum Mechanics; Applications of Modern spectroscopy

  1. Interaction of electromagnetic radiation and matter

Electromagnetic radiation. Main interactions. Radiation emission and absorption processes. Probability and width of transition. Electric dipole operator. Connection with experimental results.

 

3. Atomic and Molecular spectroscopy

The Hydrogen atom. Multi-electron atoms and molecules. Key results and spectroscopic notation.

 

4. Techniques and equipments used in spectroscopy

Sources of radiation, detectors, monochromators and interferometers, features of optic components (lenses, mirrors, windows, collimators, etc.) Reflection absorption and transmission spectroscopies. Beer-Lambert law. Experimental features that influence the intensity and width of spectral bands. Signal-to-noise ratio and resolving power of the spectrometer. Handling of optic components.

 

5. Ultraviolet photoelectron spectroscopy

Radiation sources, energy analyzer, detection and signal processing. Types of spectra. Direct ionization and self-ionization. Ressonant absorption and decay. Franck Condon factor. Angular distribution of photoelectrons. Electric  dipole selection rules. Practical application

6. Vibrational spectroscopy – Infrared and Raman

Molecular vibrations and transition rules. Normal modes of vibration. Identification of IR active modes. Anharmocity of the harmonic oscillator. Interpretation of IR spectra.

Raman scattering. Classical approach to the Raman effect. The polarizability tensor and symmetry properties. Selection rules. Polarization of transitions. Practical application.

7. X-Ray Fluorescence spectroscopy (XRF)

Production of X-Rays. X-ray Fluorescence. Components of an XRF spectrometer. Interpretation and quantification of XRF spectra. Practical application.

Bibliography

  1. Modern Spectroscopy 4th Ed. (Wiley), J.M. Hollas, 2004
  2. Atoms and Molecules, M. Weissbluth, Academic Press, 1978.
  3. Optical Spectroscopy: Methods and Instrumentations, Nikolai V. Tkachenko, Elsevier Science, 2006.
  4. Atomic and molecular spectroscopy: basic aspects and practical applications, S. Svanberg, Springer, 2004.
  5. Artigos científicos a especificar durante as aulas.

Courses