79466 - SPECTROSCOPY OF CONDENSED PHASES

Conoscenze e abilità da conseguire

The course aims at providing the student with the theoretical fundamentals for understanding, analyzing and predicting spectroscopic observables in fluid condensed phases (liquids, liquid crystals, polymers, membranes and other soft materials). The molecular description of static observables and dynamic processes (evolution equations, correlation functions , linear response theory, stochastic processes, diffusion etc..) will be presented with applications to various kind of spectroscopies: absorption, fluorescence depolarization, dielectric relaxation, NMR, X ray and neutron scattering. The prediction of observables from molecular dynamics computer simulations will also be discussed.

Contenuti

Classification of the states of matter. The solid crystal state. Binding in crystals. Crystal structure and unit cells; Bravais lattices. The crystal symmetry; a structural view of crystal symmetry: bottom-up crystallography in molecular crystals; mathematical representation of crystal symmetry; reciprocal lattice; Bloch functions.

The electronic structure of molecular solids in a simplified form. The band structure; model systems; DOS.

Excited states of aggregates of molecules; Davydov splitting and Mini-Excitons; linear molecular crystals; Frenkel Excitons; physical dimers; Excimers; Band structure; Charge transfer excitons (CT); Exciton processes; Energy transfer.

Dielectric theory of Frenkel excitons. the local field method; dielectric tensor of cubic crystals; dielectric tensor of organic anisotropic crystals

Vibrations in solids: lattice dynamics; classic description of vibrations of a one dimensional monatomic chain; vibrations of a one dimensional biatomic chain; acoustic and optic branches; extension to a tridimensional crystal. Vibrations in molecular crystals and quantisation of the vibrational energy: Phonons. Quasi particles.

Scattering: phonon-photon scattering and elastic and anelastic processes; X-ray diffraction; phonon-neutron scattering; phonon density of states.

Specific Heat of Solids: Boltzmann, Einstein, and Debye

Testi/Bibliografia

The Oxford Solid State Basics - Steven H. Simon 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

Metodi didattici

Oral Exam, with two questions and the discussion of a literature review chosen by the student.

Orario di ricevimento

Consulta il sito web di Elisabetta Venuti