This course aims at showing some techniques, based on electromagnetic radiation, for the evaluation of different properties of the materials through a practical approach. This means that the general theory behind the techniques is discussed; then the instrumentation, the sample preparation and the practical applications of the techniques are considered. An important goal is to provide the tools for the choice of the sutiable technique (in accordance to the target property) and for the interpretation of the IR spectra of materials and molecules. The course aims also at providing the knowledge of the optical properties of materials as function of their structure with also a practical activity related to the measurement of these properties in different samples.

At the end of the course and after the examination, the student should:

• Know the optical properties of materials (dispersion, scattering, absorption) and their differences according to their structure, e.g. the optical behavior of conductive and dielectric materials;
• Know the basic theory of the different characterization techniques starting from the simple models used to describe the material;
• Know the structure and the main elements of the instrumentation peculiar of the different characterization techniques also considering the methods and issues related to the sample preparation;
• Be able of choosing the suitable characterization techniques as function of the target property to be measured and the main features of the sample and apply these knowledge starting from the thesis work;
• Be able to interpret an IR spectrum in terms of main chemical groups present in the molecule/material under study;
• Be able to use simple instrumentation for the measurement of optical properties of materials (refractometer, spectrometer).

The course deals with principles and applications of widespread modern methods for material characterization. For each technique considered, the basic principles, the methods of interpretation will be shown, paying also attention to the instrumentation and sample preparation. The aim of the course is to provide tools and clarify what structural information can be obtained from the different techniques; what is the range of applicability and what are the possible options for measuring specific properties.

Table of contents (from this following list, 3-4 topics will be discussed and deepened according to the class composition and the students' learning activities).

INTRODUCTION TO SPECTROSCOPIC METHODS: Electromagnetic (EM) waves and propagation in vacuum. EM weaves-matter interaction: reflection, refraction, transmission and absorption. Energy levels in materials: quantized transitions. Elastic and inelastic scattering processes. Diffraction. Basic elements and properties of a spectroscopic instrumentation; design of a spectrograph.

OPTICAL PROPERTIES: refractive index in dielectric and conductive materials, techniques for its measurement.

ELECTRONIC SPECTROSCOPY: absorption, fluorescence, reflection electronic spectroscopy of atoms and molecules.

VIBRATIONAL SPECTROSCOPY: Normal modes of vibrations in molecules and crystals. Infrared and Raman spectroscopy.

X RAY SPECTROSCOPY: Laue approach. Reciprocal lattice, intensity analysis: Structure Factors and Electron Density.

SPIN SPECTROSCOPY: nuclear magnetic resonance (NMR) spectroscopy, electronic spin resonance (ESR) spectroscopy.

MICROSCOPY: Optical microscopy, electronic microscopy, scanning probe microscopy (SPM).

THERMAL ANALYSIS OF MATERIALS: differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA).

Laboratory activity:

For each technique discussed there will be a laboratory activity to practise with the instrumentation, sample preparation and data analysis.

A general background in physics (especially electromagnetism) and chemistry (especially organic) is useful. In any case, a brief review of these background topics is carried out during the course according to the technique under discussion.

The examination is an oral discussion covering the course topics, chosen by the examiner. Usually, there is a general question related to one key topic, then other more focused questions.

The student has to answer to the general questions contextualizing the topic, showing the key features with the help also of equations, models, schemes. Moreover, the discussion of details is welcome as well as the connections with other topics that are part of the program. The student has also to solve simple numerical exercises to support the discussion of the general topics. There is also an exercise related to the interpretation of the infrared spectra where the candidate has to assign the chemical structure to the corresponding spectrum.