Chemical sciences
Study-unit Code
Chimica fisica
Paola Sassi
  • Paola Sassi
  • 56 ore - Paola Sassi
Course Regulation
Coorte 2023
Learning activities
Discipline chimiche inorganiche e chimico-fisiche
Academic discipline
Type of study-unit
Obbligatorio (Required)
Type of learning activities
Attività formativa monodisciplinare
Language of instruction
Spectroscopy is the study of applied quantum chemistry. This course is aimed to supply the student with the fundamentals of molecular spectroscopy; in particular, the descriptions of rotational, vibrational, vibro-rotational and electronic transitions are deduced and discussed.
Reference texts
J. M. HOLLAS, High resolution Spectroscopy, Second Edition, John Wiley & Sons, 1998.
J.L. McHALE, Molecular Spectroscopy, First edition, Prentice Hall, 1999.
Educational objectives
The oral examination is aimed to test (a) the knowledge of basic concepts of time dependent quantum mechanics, (b) the knowledge of the theory and experiment of molecular spectroscopic techniques; (c) the student’s ability to clearly describe even complex concepts, by using the proper technical-scientific language, (d) the ability to design spectroscopic experiments to acquire specific information on molecular samples, (e) the ability to use the acquired knowledge to solve solely new problems as requested to a master graduate.
The achievement of points (a) and (b) defines the minimum requirement for passing the exam (threshold). Five points are awarded to point (c), four points to point (d) and three to point (e). Honors require complete knowledge of the presented topics and no corrective action by the teacher.
The student who does not pass the exam can show up after an interval of at least two weeks and, in any case, no more than twice per session. In the rare event that the student is retried more than four times, the exam can be taken only once per session.
The knowledge of mathematical analysis, electromagnetism and basic quantum mechanics is requested
Teaching methods
The course develops on frontal lecturing. At the beginning of each lesson a short summary of precedent arguments will be given to introduce the new subjects. All the basic concepts will be applied to the interpretation of literature spectra or to the solution of demonstrative exercises. The last four/six hour of the course will be devoted to a short summary of the general concepts to evidence the connections and stimulate the comparison among different experimental approaches.
Other information
attendance is recommended
Learning verification modality
The verification of learning consists of a single oral test of thirty/forty-five minutes. At the beginning of the test, the candidate will present a topic chosen from the program, for about ten minutes; then, he/she will be requested to answer to questions on the other arguments of the course.
Extended program
1. Introduction to molecular spectroscopy
Electric properties of matter. Schröedinger equation and Born-Oppenheimer approximation. molecular degrees of freedom. Time perturbation theory. Einstein coefficient. Natural band-width. Lambert-Beer Law
2. General requirements of spectroscopic instrumentations
Sources and detectors. Monocromators. Fabry-Perot and Michelson interferometers
3. Rotational spectroscopy of diatomics
The rigid rotor: classic and quantum mechanics descriptions. Energy levels, population, selection rules and rotational spectra. Stark effect. Correction to the rigid rotor approximation
4. Rotational Raman Spectroscopy
Rayleigh and Raman diffusion. Polarizzability ellipsoid. selection rules of raman effect. Rotational Raman spectra of diatomics. Raman spectrometers. Nuclear statistics. and J states of homonuclear diatomics
5. Rotational spectroscopy of polyatomic molecules
Moments of inertia. Inertial ellipsoid and classification of rotors. Linear molecules and rotational spectra; Stark effect. Rotational spectra of symmetric tops: absorption and diffusion. Spectra of asymmetric tops
6. Vibrational spectroscopy of diatomics
The harmonic oscillator model: classical and quantum mechanics description. Energy level, selection rules and IR spectra. Anharmonic potential and dissociation energy. Vibrational Raman scattering. Scattering geometries and polarization properties.
7. Vibrational spectroscopy of polyatomics
Molecular degrees of freedom. Normal modes of vibration: classical equations of motion. Group frequencies. Elements of group theory. The symmetry of normal modes. raman and IR selection rules. Selection rules at work: the case of H2O.
8. Vibration-rotation spectroscopy
Selection rules in case of rigid rotor-harmonic oscillator approximation. Roto-vibrational coupling. Parallel and perpendicular bands of linear and symmetric top molecules.
9. Electronic spectroscopy of diatomics
Classification of electronic states. Selection rules. Vibronic structure. progressions and sequences. Deslandres tables. Rotovibronic structure and Fortrat curves. Dissociation energies
10. Resonance Raman Scattering
Kramers-Heisemberg-Dirac description of raman effect. Resonant enhancement. Interfering factors in the measure of resonant raman radiation. Franck-Condon resonance and the vibronic coupling. Excitation profiles of Raman bands.
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