spring 2020

## KJE-2001 Molecular physical chemistry and foundations of spectroscopy - 10 ECTS

## Admission requirements

The course requires basic calculus knowledge (either Mat-0001 or Mat-1001 is required. If Mat-0001 is chosen, it would be better to also include Mat-1002, for completeness). and basic physical chemistry knowledge (KJE-1005 course or equivalent). Basic knowledge in physics (elementary classical mechanics and electromagnetism) is an advantage, as well as elementary linear algebra.## Course content

Atoms and molecules are the tiniest building blocks of anything that surrounds us. They are so small that they challenge the physics which we are used to. Indeed they no longer abide to Newton's laws but they behave according to the laws of Quantum Mechanics. This is challenging as Quantum Mechanics clashes with our common sense, but also fascinating, making it possible to reveal and exploit the unique properties of atoms and molecules: the technological world we are used to, with powerful computers in the palm of our hands (a modern smartphone could have easily made it to the top-100 supercomputer list 20 years ago!) heavily relies on the quantistic properties of matter for the construction of the necessary components. Investigating atoms and molecules is challenging: to "measure" them we need to make use of even smaller particles: photons. The interaction of matter with photons give rise to a wide range of spectroscopic methods which are among a chemist's finest tools. Some spectroscopic techniques such as infrared spectroscopy are now routinely performed in any chemistry lab. Others such as Magnetic Resonance are not only a powerful investigation method of molecular structure but have extended far beyond chemistry to biology and medicine. In the present course the foundation of Quantum Mechanics will be presented: after a historical introduction (discovery of quanta, balck-body radiation, electron diffraction, photoelectric effect) the postulates of quantum mechanics and their interpretation will be presented. We will then connect them to some simple exact models (harmonic oscillator, particle on a sphere, hydrogenionic systems) emphasising the aspects connected to atomic and molecular structure. We will then turn our attention to the electronic structure of atoms and molecules. The simplest electronic structure models and tools (atomic orbitals and electron correlation, LCAO, molecular orbitals, Hückel¿s model) will be semi-quantitatively presented. The link from the molecular level to the macroscopic world, statistical mechanics shall be introduced: a macroscopic system is a large collection of molecules which must obey strict statistical laws, providing a sound molecular interpretation for classical thermodynamics. We will finally focus on spectroscopic techniques. We will describe how molecules interact with light (photons) at different frequency giving rise to a variety of methods addressing important questions about molecular structure: such as bond lengths and strengths, connectivity, electronic states, intermolecular interactions. Among the techniques that will be presented are Rotational spectroscopy, Vibrational spectroscopy, Electronic spectroscopy, Raman techniques, Nuclear Magnetic Resonance, Electron Spin Resonance. The first three will be discussed in detail, whereas the other three will only briefly touched upon. Spectroscopic techniques are a vast subject: by no means the present course could cover all of them. Students are therefore encouraged to put forward specific techniques they wish to learn about so that they could be covered during the course, at least in their general aspects.## Objectives of the course

**Knowledge:** The candidate¿

- will use the postulates of quantum mechanics to solve exactly the simplest systems: particle in a box, particle on a circle
- will explain the features of such models in light of their respective wavefunction
- will analyze more advanced solvable models (particle on a sphere, harmonic oscillator, hydrogen atom) through the knowledge of the easier ones (box, circle)
- will be able to explain the features of atomic and molecular systems in light of the knowledge acquired about solvable models
- will be able to explain the Boltzmann distribution and the partition function
- will be able to describe the main general features of spectroscopic methods to investigate the molecular structure
- will use the acquired fundamental knowledge to interpret simple rotational, vibrational and vibrational-rotational spectra
- will be able to describe the main features of electronic spectra and the underlying dynamics of the excited states
- will be able to identify and describe the fundamental features and underlying principles of more advanced spectroscopic techniques: Raman spectroscopy (vibrational and rotational), Magnetic spectroscopy (NMR, EPR).

**Skills:** The candidate¿

- will be able to solve simple problems for the model systems (particle in a box, particle on a circle/sphere, harmonic oscillator, hydrogen atom)
- will explain atomic properties/structure and spectroscopy in light of the principles of quantum mechanics and the solvable models
- will relate the main features of molecular spectroscopy (e.g. band structure, band intensity, shape, energy range) to the acquired knowledge of quantum mechanics
- will be able to explain the details of simple molecular spectra and relate them to the molecular structure (e.g. bond length and strength, connectivity, electronic structure)
- will be able to explain and make use of the Hückel model to explain the electronic structure of conjugated compounds, with particular reference to the concept of aromaticity
- will be able to make use of statistichal mechanics to explain observable phenomena such as features of molecular spectra, heat capacities, phase transitions.

**General competence:** The candidate...

- will be able to explain the main traits of quantum mechanics and the main differences with respect to classical mechanics
- will be able to use quantum mechanics arguments to describe the structure of atoms and molecules
- will be able to analyze the main features of atomic and molecular spectra, relating them to the molecular structure and to the underlying laws of quantum mechanics
- will be able to connecthrough statistical mechanics and the molecular partition functions. t molecular structure to thermodynamic quantities (free energy, heat capacity) through statistical mechanics and the molecular partition functions.

###### Kontakt

### Renate Lie Larsen

Seniorkonsulent, studieadministrasjon, Innkjøper institutt for kjemi,

Telefon: +4777644074 renate.larsen@uit.no

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