Unit FEMTOCHEMISTRY

Course
Chemical sciences
Study-unit Code
GP000986
Curriculum
In all curricula
Teacher
Benedetta Carlotti
Teachers
  • Benedetta Carlotti
Hours
  • 42 ore - Benedetta Carlotti
CFU
6
Course Regulation
Coorte 2020
Offered
2021/22
Learning activities
Affine/integrativa
Area
Attività formative affini o integrative
Academic discipline
CHIM/02
Type of study-unit
Opzionale (Optional)
Type of learning activities
Attività formativa monodisciplinare
Language of instruction
Italian
Contents
Basic principles of Non-Linear Optics and Photophysics. Description of the main femtosecond resolved spectroscopic techniques both in absorption and in emission. Study of ultrafast processes of excited state deactivation (charge, energy, proton transfers and photochemical reactions) in organic compounds of different kind (Femtochemistry) and in biological macromolecules (Femtobiology).
Reference texts
A. Douhal, J. Santamaria, FEMTOCHEMISTRY AND FEMTOBIOLOGY, 2001, World Scientific.
F. C. De Schryver, S. De Feyter, G. Schweitzer, FEMTOCHEMISTRY, 2001, Wiley.
M. A. El Sayed, I. Tanaka, Y. Molin, ULTRAFAST PROCESSES IN CHEMISTRY AND BIOLOGY, Blackwell Science.
Educational objectives
The student will become familiar with the most important concepts of Femtochemistry and will acquire knowledge about the advanced spectroscopic techniques used for the study of ultrafast processes.
Prerequisites
In order to understand the topics covered in the course, basic knowledge of Molecular Spectroscopy and Chemical Kinetics are required. These issues will be addressed in some lessons that will be held at the beginning of the course of Femtochemistry.
Teaching methods
Lectures with slide projections. Some lessons will be dedicated to the deepening of the addressed issues, some others to the visit of the ultrafast spectroscopy laboratory of our department.
Other information
Tutoring activity is planned during the course and for the students who request it to assist them in the preparation of the exam.
Learning verification modality
The exam consists in an oral test. The oral examination is a discussion lasting about 30 minutes aimed at ascertaining the level of knowledge and understanding reached by the student on the topics listed in the program. The oral exam will also serve to verify the communication skills of the student and ability in autonomous organization of the exposition.
Extended program
Concepts of optics. Light and its propagation in vacuum and in a dielectric medium. Second order polarisation: second-harmonic generation; sum- and difference- frequency generation. Third order polarisation: white light generation and two-photon absorption. Light pulses: dispersion.

Concepts of photophysics and photochemistry. Absorption of light and deactivation of electronic excited states: rates of the processes. Solvation. Polarisation and molecular orientation. Excitation energy transfer. Electron transfer.

Ultrafast spectroscopic techniques. Ultraviolet-visible transient absorption. Fluorescence up-conversion: examples of broadband and high temporal resolution experimental set-ups. Infrared transient absorption. Two-dimensional infrared spectroscopy. Two photon excited fluorescence. Surface second-harmonic generation spectroscopy.

Femtochemistry. Photoinduced intramolecular charge transfer (ICT) in push-pull systems: excited state dynamics; effect of solvent polarity and viscosity. Bimolecular photoinduced electron transfer (BPET): electronic coupling and solvation; examples in organic photovoltaics. Excitation energy transfer in multichromophoric systems. Excited state intra/intermolecular proton transfer (ESIPT): photoacids and photobases. Excited state dynamics of probe molecules at the liquid/liquid interfase. Two-photon absorption of fluorophores, systems for photodynamic therapy of cancer and initiators for microfabrication.

Femtobiology. Cis-trans isomerisation in vision: a classic ultrafast photochemical reaction. Ultrafast spectroscopy to investigate DNA and protein dynamics.
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