Structure of molecules. The molecular orbital method. Expansion in atomic orbitals. Symmetry of molecules. Group theory and irreducible representations. The orthogonality relations. Symmetry properties of the molecular states. Rotational spectra of linear molecules and of symmetric rotors. The vibrational spectrum of molecules. Infrared and Raman spectroscopy. The rotational structure of the vibrational bands. Electronic transitions in polyatomic molecules. The Franck-Condon principle.
Knowledge acquired:
Molecular orbital theory. Group theory and theory of representations. Principles of the absorption and scattering spectroscopy of molecules.
Competence acquired:
Classification of the rotational, vibrational and electronic state of polyatomic molecules. Symmetry of the molecule and spectroscopic selection rules
Skills acquired (at the end of the course):
Analysis of the infrared and Raman spectra on molecules and bands assignment to normal modes and symmetry species. Analysis of the electronic spectra and of their fine structure. Correlation of the rotational and vibro-rotational structure with the molecular structure.
Teaching Methods
Total hours of the course (including the time spent in attending lectures, seminars, private study, examinations, etc...):
75
Hours reserved to private study and other individual formative activities:
47
Contact hours for: Lectures (hours): 25
Office hours:
The students contact the teacher at any time.
Type of Assessment
Written report on the interpretation of vibrational and electronic spectra and discussion of the report.
Course program
Language of instructions: Italian
Course Contents (detailed program):
Structure of molecules. The molecular orbital method. Expansion in atomic orbitals. Symmetry of molecules. Group theory and irreducible representations. The orthogonality relations. Symmetry properties of the molecular states. Rotational spectra of linear molecules and of symmetric rotors. Levels population and rotational structure. Rotational – vibrational interactions. The vibrations of molecules. Normal modes. Normal coordinates. Quantum treatment of the vibrations of polyatomic molecules. Use of the internal coordinates. Classification of the normal coordinates in symmetry species. Selection rules for absorption and scattering processes. Infrared and Raman spectra. Vibrationa assignments: Raman lines polarization and vibro-rotational contours. Electronic transitions in molecules. Fine strtructure of the electronic transitions in diatomics. Electronic spectra of polyatomic molecules. Classification of the transitions. Vibronic transitions and selection rules. Spectra of conjugated molecules. Fluorescence and phosphorescence spectra.