66190 - Physical Chemistry of the Solid State M

Course contents

Each of the points indicated below comprises ca 120 minute of lectures in class.

• Introductory Remarks about the course. Time dependent perturbation theory.
• Classification of empirical optical processes. Optical coefficients; Beer’s law; The complex refractive index and dielectric constants
• Introduction to Classical theory of light propagation. Electric properties of molecules and bulk matter; The charge distribution in molecules; Review of electrostatics; Electric moments; Interaction of electric moments with the electric; field Polarizability and induced moments.
• Classical model of light propagation. Frequency dependence of the induced dipole moment: the Lorenz oscillator; Multiple resonances; Local field corrections; The Kramers–Kronig relationships; Solid state materials and their classification from an optical point of view
• Types of condensed phases: General Classification e properties.
• Crystal Structures: Bravais lattices; unit cells; Wigner–Seitz cell. Crystal symmetry: A structural view of crystal symmetry: bottom-up crystallographywithexamples.
• The mathematical representation of space group symmetry. Translations; Factor group. Space group representations; Reciprocal lattices
• Bloch’s Functions; The properties of the crystal periodicity; The electronic structure in (molecular) solids; the band structure in very simple systems.
• Molecular organic crystals. Electronic spectra of crystals vs isolated molecules. Effects due to Polarization: example of tetracene in molecular beam; Statistical averaging and polarization.
• Davydov Splitting and Mini-Excitons: the model of a crystal with two non-equivalent molecules/cell and the resonance interaction energy. Strenght of the interactions; Excimer formation. Polarization of the optical transitions involving Davydov's components.The Frenkel Exciton Concept for Two Molecules per Unit Cell;
• Definition of J and H aggregates and their absorption and emission spectra;
• The Frenkel Exciton Concept for Two Molecules per Unit Cell; The extension to 3D infinite crystals and the Frenkel Excitons in molecular systems.
• Charge transfer Excitons. Excitons and mechanisms of energy transfer. Exciton Processes, Energy Conduction; Förster and Dexter Type Energy transfer. Examples
• Charged Systems; Devices with charge transport. OSC, OLED, OFETS. Processes involved in adding or removing a charge to or from one molecule in a solid. Generation of charged Molecules; Energy levels in charged molecules; Spectroscopy of charged molecules.
• Dynamics of molecules and of lattice in molecular crystals. Vibrations in one-dimentional atomic chain. The model extended to a diatomic linear chain. General extension to 3D systems. Internal and external vibrations in molecular crystals
• Phonons in the description of quantum mechanics. Vibrations in molecular Crystals. Phonon-Photon Scattering: light- matter interaction as scattering between particles. Phonon - photon (IR, UV-Vis, Xray) scattering phenomena, classified as elastic and inelastic and corresponding spectroscopies. Description of phonon-neutron scattering.
• Symmetry analysis of the vibrational spectrum of organic molecular crystals: Factor group analysis. Rigid molecule approximation and symmetry analysis of external vibrations.IR and Raman selection rules.
• At the end of the course, students will be presented a number of research articles on subjects related to the course topics. Each student will choose one to discuss as a part of the oral exam.

Readings/Bibliography

ach of the folllowing texts comprises some chapters which cover topics dealt with in the course.

They must be taken as "suggested readings". The lecturer's Notes and slides will be available at the IOL website and/or will be shared with the class on the lecturer's Alma Mater OneDrive, together with research articles and useful notes.

Optical properties of Solids- Mark Fox Oxford University Press

Molecular Aggregation Angelo Gavezzotti - IUCR book series Oxford University Press

Organic Molecular Solids - Markus Schwoerer, Hans Christoph Wolf Wiley-VCH

Electronic Processes in Organic Semiconductors -Anna Köhler and
Heinz Bässler , Wiley-VCH

Teaching methods

Lectures in the class.

Assessment methods

The exam consists of an oral test, with two questions about the subjects treated in the course and the discussion of a research paper chosen by the student from those selected by the lecturer on topics related to the course syllabus.

Teaching tools

Students will find on IOL both the lecture notes and the slides presented during the lectures (in english and Italian)

Office hours

See the website of Elisabetta Venuti