Physical Chemistry II and Laboratory M - Z

Module Physical Chemistry II and laboratory (Module 1)

The course aims to provide the physico-chemical basic knowledge for understanding the chemical bond, the molecular spectroscopy and the chemical kinetics. Specific objectives: at the end of the course the student will be able to understand the basic principles of quantum mechanical and spectroscopic methods and their application to the determination of the electronic and geometric structure of simple molecular systems, the laws and the basic theories of chemical kinetics as well as the main methods for the theoretical and experimental study of chemical reactions.

Moreover, in reference to the so-called Dublin Descriptors, this course helps to acquire the following transversal skills:

• Knowledge and understanding: getting to know the reasons for the crisis of classical physics and the origin of quantum mechanics; knowledge of the fundamentals of quantum mechanics and the principles that govern the electronic structure of atoms and molecules; knowledge of the basic principles of light-matter interaction.

• Applied knowledge and understanding: application of the acquired knowledge for the description of chemical bonds (introduction to nanosciences), for molecular spectroscopy, photophysical and femtochemical processes.

• Making judgments: gathering and interpreting relevant data, critical reasoning skills, ability to identify the predictions of a theory or a model.

• Communication skills: ability to describe a scientific topic in both written and oral form, with properties of language and terminological rigor, explaining the reasons and results.

• Learning skills: to have developed the necessary skills to undertake subsequent studies with a high degree of autonomy.

Frontal lessons with projector and blackboard; exercises.

Should teaching be carried out in mixed mode or remotely, it may be necessary to introduce changes with respect to previous statements, in line with the programme planned and outlined in the syllabus.

I - Quantum description of atoms and molecules structure.

Crisis of classical physics and the origin of quantum theory. Postulates of quantum mechanics. Wave functions and operators. Schroedinger equation. The particle in a potential well. Harmonic oscillator and anharmonic. Rigid rotator. The hydrogen atom. Approximate methods for solving the Schroedinger equation: perturbation methods; variational method. The helium atom. Angular momentum and spin states. Variational principle and mean field theory for atoms with more electrons. Orbital approximation. Method of Hartree-Fock. Correlation Energy. Independent Electron Theory for complex atoms. Pauli principle. Aufbau.

The chemical bond and diatomic molecules. Born-Oppenheimer approximation. The molecular orbital method and application to the hydrogen molecule ion. Overlap integrals, Coulomb and exchange and their contribution to the stability of the chemical bond. Molecular orbitals of bonding and antibonding. Diatomic molecules with more than one electron. Electronic structure in the MO diagram. Orbital σ and π - Application of the method of molecular orbitals aufbau - Electronic configuration and properties of diatomic homonuclear molecules.

Polyatomic molecules. The Huckel method. Relocation Energy. Calculation of charge distributions for a π system. Bond order π and total. Extension of the Hückel method to compounds containing heteroatoms. Experimental evidence of the existence of molecular orbitals. Introduction to electronic structure of solids.

II - Light-matter interaction and molecular spectroscopy.

Basic principles of molecular spectroscopy. Interaction electromagnetic radiation with matter. Time-dependent perturbation theory. Born-Oppenheimer approximation for spectroscopy.

Rotational Spectroscopy. energy levels rotational and rotational spectra of diatomic molecules. Classification of molecules from a rotational standpoint and their spectra: linear rotators, symmetrical oblates and prolates, spherical, asymmetrical.

Vibrational spectroscopy. Vibrational spectra of diatomic molecules and selection rules according to the harmonic oscillator model. Application of the anharmonic oscillator model - Normal modes of a polyatomic system and vibrational spectra. Vibro-rotational spectra of two-, and triatomic molecules.

Electronic spectroscopy. Electronic transitions in diatomic and polyatomic molecules. Selection rules. Franck-Condon principle and vibronic transitions. Photoelectron spectroscopy. Electronic excited states. Photophysical processes. Einstein coefficients, spontaneous emission and stimulated emission. Fluorescence Spectroscopy.

Lasers and laser spectroscopy. Photochemical processes.

III - Chemical Kinetics.

Rate of chemical reactions. Kinetic laws and kinetic rate constants. Integration of simple kinetic equations. Dependence of the reaction rate from the temperature. Reaction mechanisms. Elementary reactions. Consecutive and parallel reactions. Detailed balance principle. Approximation of the stationary state. Complex reactions. Enzyme kinetics. The dynamics of reactions. Collision theory: sphere of collision, shock section, shock energy and steric factor. Transition state theory. The experimental study of molecular collisions. Angular distribution and of the speed of the reaction products. Bounce mechanisms, stripping and with complex formation. Potential energy surfaces. The study of ultrafast reactions: femtochemistry.

1. Handouts and lecture slides provided by the teacher.
2. P. Atkins, J. de Paula - PHYSICAL CHEMISTRY 9th Ed- W.H. FREEMAN AND COMPANY New York / P.W. Atkins, J. de Paula, J. Keeler - Chimica fisica (6a edizione) - Zanichelli
3. P. Atkins, J. de Paula, R. Friedman - QUANTA, MATTER, AND CHANGE: A MOLECULAR APPROACH TO PHYSICAL CHEMISTRY -W.H. FREEMAN AND COMPANY New York.
4. D.A.Mc.Quarrie, J.D. Simon – CHIMICA FISICA un approccio molecolare -  Zanichelli
5. J.M. Hollas, MODERN SPECTROSCOPY - Wiley

Written and oral. The final examination consists of a written exam (the day of the exam is as indicated on the official calendar), based on exercises similar to those covered in the classroom during the course, and an oral interview (date and place will be indicated by the lecturer) based on all the arguments of the program. Students will be allowed to use the periodic table and calculator during the written exam, not mobile phones.