OVERVIEW

The course is devoted to the diffraction techniques for the study of crystalline materials.

AIMS AND CONTENT

LEARNING OUTCOMES

The aim of the course is to provide basic knowledge on the diffraction theory, on the most common experimental techniques and their possible use, so that the student is able to understand and interpret diffraction data and to solve simple crystallographic problems.

AIMS AND LEARNING OUTCOMES

The course aims at using the theoretical concepts of diffraction to analyze and interpret diffraction data (both on powders and single crystals) from a practical point of view. At the end of the lessons the student will be able to correctly interpret and use the International Tables of Crystallography, and will have acquired useful knowledge for the characterization of crystalline materials. In particular, the student is expected to know the fundamental equations and expressions of the theoretical part (Laue equations, Bragg's law, scattering factor and structure factor, electronic density) and to describe/discuss their meaning. Moreover, the student is expected to be able to interpret structural data, to analyse simple powder diffraction patterns, identifying the phases present through indexing and calculation of the lattice  parameters. In addition, the student should be able to set a structural refinement on single crystal data, and on powder data using the Rietveld method.

TEACHING METHODS

The course will be done in a traditional way, with lectures and exercises. The lectures will be interspersed with exercises and examples carried out with the contribution of all students.

In addition, topics will be identified among those not directly addressed in class but closely related to the contents of the course, as possible subjects for further study by the students. In this case, the deepening and further study (both individual and in small groups) will be completed in a session of presentation and discussion, which will be shared by the whole class.

Usually, the practical experiences are activities carried out by means of a computer; they take place in the classroom for groups of students

SYLLABUS/CONTENT

The course is worth 6 CFU, corresponding to a total of 150 hours of study. They are divided in 36 h of lectures, 20 h of practical activities/exercises in class, 94 h of individual study by the students.

- Elements of elementary crystallography: symmetry elements, crystal lattices, point groups, space groups. Planes and crystallographic directions. Description and use of the International Tables of Crystallography.

- Diffraction theory : Nature and production of the RX. Safety and practical considerations. X-ray diffraction and neutron/electron diffraction (notes). Scattering factor and structure factor. Laue equations, Bragg's law, reciprocal lattice, Ewald sphere.

- Experimental techniques: Diffraction from polycrystalline samples and single crystals. Sample preparation and data collection strategies. Use of crystallographic databases.

- Resolution and structural refinement: The intensity of the diffraction peaks. The electron density. The phase problem. Solution methods: synthesis of Patterson, direct methods.

Practical exercises: Indexing and identification of the phases present in a polycrystalline sample; structural refinement with the Rietveld method; structural resolution "ab initio" using of intensity data from single crystal and/or structural refinement on the basis of a known model.

RECOMMENDED READING/BIBLIOGRAPHY

Besides the material available on Aulaweb, the following textbooks are recommanded:

A. Immirzi, C. Tedesco, “La diffrazione dei cristalli” 2a Edizione. Cooperativa Universitaria Athena

C. Giacovazzo, H.L. Monaco, G. Artioli, D. Viterbo, G. Ferraris, G. Gilli, G. Zanotti, M. Catti “Fundamentals of Crystallography” Ed. C. Giacovazzo

M.F.C. Ladd, “Symmetry in molecules and crystals”

G.H.Stout, L.H.Jensen, “X-ray structure determination”, Macmillan Publishing Co, N.Y (1968)

V. K. Pecharsky, P. Y. Zavalij, “Fundamentals of powder diffraction and structural characterization of materials”

Kluwer Academic Press

Tabelle Internazionali di Cristallografia Vol.1-4

TEACHERS AND EXAM BOARD

LESSONS

LESSONS START

From 28 February 2024

Class schedule

The timetable for this course is available here: Portale EasyAcademy

EXAMS

EXAM DESCRIPTION

Students can choose two different methods of examination: 1) traditional oral exam on various topics covered during the course. Usually three questions, one of which is on the theoretical part, one on experimental techniques, one on aspects concerning the interpretation and analysis of structural data. 2) An in-depth essay on a topic of crystallography, previously agreed. For the latter method both a written report and an oral presentation are required. The oral examination is always conducted by two faculty members and on average has a duration of at least 40 minutes; the commission will thus be able to verify wether the educational objectives are reached or not . When these are not met, the student is invited to deepen the study and to use further explanations by the teacher

ASSESSMENT METHODS

The oral exam is aimed at verifying: 1) the achievement of a proper knowledge level on the topics covered during the lessons; 2) the usage of the correct terminology; 3) coherence in the exposition of the concepts. To pass the exam, students must demonstrate the effective acquisition of the diffraction theory concepts, and their application to real situations.

Both the reasoning ability of the students and their ability to solve simple theoretical and/or practical problems are evaluated.

FURTHER INFORMATION

Students who have valid certification of physical or learning disabilities on file with the University and who wish to discuss possible accommodations or other circumstances regarding lectures, coursework and exams, should speak both with the instructor and with Professor Sergio Di Domizio (sergio.didomizio@unige.it), the Department’s disability liaison.