MOLECULAR PHOTONICS

Credits: 
6
Site: 
PARMA
Year of erogation: 
2020/2021
Unit Coordinator: 
Disciplinary Sector: 
PHYSICAL CHEMISTRY
Semester: 
First semester
Language of instruction: 

Italian

Learning outcomes of the course unit

Knowledge and understanding
Students will learn advanced concepts in optical spectroscopy and in molecular photonics and multifotonics, including in-depth fundamental knowledge on the theories of energy transfers and charge transfers, as well as an introduction to advanced techniques and applications in nonlinear and time-resolved spectroscopy. They will consolidate and exploit the basic knowledge acquired in previous years concerning molecular spectroscopy and quantum mechanics, to tackle more advanced concepts, with an opening on the most interesting and current application techniques in the fields of biomolecular chemistry and molecular materials.

Applying knowledge and understanding
The student will have the ability to investigate some fundamental processes of biomolecular chemistry and materials, such as energy and charge transfers, as well as designing the use of multiphoton optical microscopy techniques. She/he will be able to plan and carry out advanced spectroscopic experiments and have the necessary bases for the interpretation of the results and to obtain important information on the systems of interest.

Making judgements
The student will be able to independently evaluate the structure-property correlations using the most modern techniques of spectroscopic investigation and optical microscopy. She/he will know the fields and limits of use of nonlinear spectroscopies, of the methods based on excitation energy transfer and of the Marcus theory for electron transfers. She/he will be able to design experimental activities in the field of optical spectroscopy, know how to evaluate and quantify the experimental results; she/he will be able to adapt to different working environments and themes involving the spectroscopic/optical properties of biomolecules and materials.

Communication
The student will be able to communicate in depth on issues related to optical, linear and nonlinear spectroscopy and its application to biomolecules and materials.

Lifelong learning skills
Thanks to a critical approach to problems, the student will be able to learn autonomously and tackle new scientific issues or professional problems concerning the spectroscopic/optical properties of biomolecules and materials, even in interdisciplinary fields.

Prerequisites

Basis knowledge in quantum-mechanics and molecular spectroscopy.

Course contents summary

Excitation energy transfer; Fluorescence anisotropy; Electron transfer; Laser; Nonlinear optics; Optical microscopy; Time-resolved spectroscopy; Optical Bloch equations and photon echo; Two-dimensional IR spectroscopy.

Course contents

REVISION OF SOME BASIC CONCEPTS IN OPTICAL SPECTROSCOPY
- Absorption spectra (Franck-Condon factors, transition dipole moment, oscillator strength)
- Luminescence spectra (Jablonski diagrams, Kasha rule, luminescence quantum yield, luminescence lifetimes)

ENERGY TRANSFER
- Förster and Dexter mechanisms
- FRET (Fluorescence Resonance Energy Transfer) applications: macromolecular association and intermolecular distance investigation; protein folding; energy harvesting; sensing

FLUORESCENCE ANISOTROPY

ELECTRON TRANSFER
- Classical transition-state theory
- Marcus model (classical, semiclassical e quantum-mechanical) and applications to molecular systems
- Mulliken-Hush charge-transfer theory

LASERs

NONLINEAR OPTICS
- Nonlinear response theory: n-th order hyperpolarizabilities
- Parametric and non-parametric processes
- The role of symmetry
- Second-order processes: general overview of the processes + detailed treatment of second-harmonic generation and its applications
- Third-order processes: general overview of the processes + detailed treatment of two-photon absorption (TPA) and Raman scattering (and relevant applications)

OPTICAL (MULTIPHOTONIC) MICROSCOPY
- Confocal microscopy
- Multiphoton optical imaging
- Super-resolution optical microscopy

TIME-RESOLVED SPECTROSCOPY
- Heller method
- Fluorescence up-conversion
- Pump-probe spectroscopy

OPTICAL BLOCH EQUATIONS AND PHOTON ECHO

TWO-DIMENSIONAL IR SPECTROSCOPY

Recommended readings

J. R. Lakowicz, Principles of Fluorescence Spectroscopy, Springer 2006.
V. May, O. Kuhn, Charge and Energy Transfer Dynamics in Molecular Systems, Wiley 2004.
R. W. Boyd, Nonlinear Optics, Academic Press 2008.
Y. R. Shen, The Principles of Nonlinear Optics, Wiley-Interscience 1984.
P. Hamm and M. Zanni, Concepts and Methods of 2D Infrared Spectroscopy, Cambridge University Press 2011.

Teaching methods

Classes (in the classroom and online) + examples though pictures and videos.

Assessment methods and criteria

Knowledge and understanding, applying knowledge and understanding, making judgements, communication and learning skills are verified through an oral examination. The exam is typically organized into 2/3 questions, related to 2/3 basic topics of the course. The evaluation scale is divided into: 18-23 = basic knowledge of the techniques and of the theories at their base; 24-27 = ability to discuss techniques (with advantages and limitations) and the implications of the theoretical approaches; 28-30 = demonstration of critical autonomy in the understanding of the theoretical approach to spectroscopic/optical properties, relevant techniques and the approximations introduced in the interpretation of the data. The test lasts about 45 minutes.

Other informations

Besides a wide bibliography, detailed notes on each of the course's subjects are made available to the students.