79466 - Spectroscopy of Condensed Phases

Learning outcomes

Modern research in chemistry and materials science involves the interaction of radiation with condensed-phase systems such as molecules in liquids and solids as well as aggregates, metals, semiconductors, and composites. The course aims to provide the student with a basic description of a number of spectroscopic phenomena associated with such systems, with elementary treatments of fundamental theoretical concepts. Starting from the basics of traditional molecular spectroscopy, optical processes will be treated with emphasis on the condensed phase perspective, to include metals, glasses and molecular crystals. Experimental techniques will be addressed with the goal of understanding spectroscopic data

Course contents

Classification of the states of matter. The solid crystal state: Crystal structures: Bravais lattices;unit 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.

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.

Readings/Bibliography

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

 

Lecture notes and slides

Assessment methods

Oral Exam, with two questions and the discussion of a research paper chosen by the student and dealing with one of the course topics.

Office hours

See the website of Elisabetta Venuti