Experimental Physical Chemistry - Seminar Topics

For your seminar talk you can suggest 3 favorite topics from the following list. It is also possible to suggest your own topic, if it fits into the context of your course. The provided keywords shall serve as an ortientation. Please consult with your teaching assistant regarding the outline of your talk.

Spectroscopy Course

Electric Properties: Polarizability, permanent and induced dipole moment, higher-order moments, displacement and orientation polarization, molar polarization, dielectric constant, index of refraction, molar refraction, measurement of dipole moment; intermolecular interactions (e.g. dipole-dipole, dipole-quadrupole interaction, etc.)
Atomic and Molecular Spectroscopy: Interaction of electromagnetic radiation with matter, transition dipole moment, Einstein coefficients, absorption line intensity and broadening (life time, collisional, Doppler), term symbols of atoms and molecules, Hund’s rules, selection rules, Doppler-free (sub-Doppler) spectroscopy, AAS, LIF, REMPI
UV/vis Spectroscopy: Franck-Condon principle, absorption and emission spectra, couplings, Jablonski diagram, fluorescence, phosphorescence, determination of dissociation energies (Birge-Sponer plot), pre-dissociation, experimental techniques
IR Spectroscopy – Theory: Rotation- and vibration spectra, harmonic and Morse oscillator, wavefunctions, selection rules, double harmonic approximation, Fortrat parabola, determination of rotational temperatures, vibrational normal modes
Fourier-Transform Infrared Spectroscopy: Experimental implementation: Michelson interferometer, cube-corner interferometer, IR optics, IR detectors, single and double-sided interferogram; Data evaluation: Fourier transformation, FFT, apodisation, zero-filling
Raman Spectroscopy – Theory: Smekal-Raman effect, Stokes-, Anti-Stokes- and Rayleigh-Scattering, selection rules, comparison IR/Raman, nuclear spin statistics, mutual exclusion rule
Raman Spectroscopy – Experiment: Typical Raman setup: spectrograph (Czerny-Turner design, diffraction grating, types of gratings, grating efficiency, diffraction order, resolution), CCD detector (working principle, quantum efficiency, types of noise); techniques: tip-enhanced Raman spectroscopy, surface-enhanced Raman spectroscopy, Raman microscopy
Laser Theory: Population inversion, lasing threshold, 3- and 4-level lasers, resonator modes; laser types: solid state, gas, excimer, dye, semi-conductor (typical application areas); generation of short pulses (e.g. Q-switch), generation of narrow lines
Lasers in Practice: Understanding laser specifications: output power, wavelength, single- vs. multi-mode, line width, beam diameter, beam divergence, M², pointing stability, power stability, RMSE noise, polarization; spectroscopic applications, e.g. direct laser absorption spectroscopy, wavelength modulation spectroscopy, cavity ring-down spectroscopy, photo-acoustic spectroscopy, double resonance spectroscopy, FRET, etc.
Optical Sensors: Working principle; photo diode, pyroelectric sensor, bolometer, CMOS, CCD, photo multiplier, MCP, FPA (focal plane array); applications, detection limits

Kinetics Course

Transport and Flow Processes

General transport equation, diffusion, heat conductivity (also convection), viscosity. Simple theory of laminar and turbulent flow, use of flow-systems for kinetic studies.

Collision Processes

Collision theory, differential collision cross-sections, measurement of collision crosssections, collision frequency, mean free path, kinetic gas theory, Maxwell-Boltzmann distribution (1-D, 2-D, 3-D)

Transition State Theory

Transition state theory (Evans-Polanyi, Eyring), relation to thermodynamics, energy hypersurfaces, trajectories, deviation from Arrhenius behavior (tunnel effect etc.), ab-initio calculations.

Unimolecular Reactions (1)

Lindemann, Hinshelwood, fall-off region, comparison to experiment

Unimolecular Reactions (2)

RRK(M) theory, Tolman, comparison of E_a and E₀.

Femtochemistry

fs-laser pulses, mode-locking, bond breakage, spectroscopy in the near-TS region, lifetime determination of transition state complexes

Energy conversion during collisions with a surface

Molecular beam experiments, measurement of particle velocities, resonance-enhanced multiphoton ionization (REMPI), energy transfer between translational, vibrational, and rotational degrees of freedom, energy transfer to phonons and electrons of the surface, nonadiabaticity (breakdown of the Born-Oppenheimer approximation)

Nucleation and particle growth

Supersaturation, kelvin effect, condensation, Köhler theory, coagulation, critical cluster size, classical nucleation theory, measurement of nucleation rates, environmental aspects

Environmental kinetics (one of the two)

Ozone hole: Seasonal variation, influencing reaction cycles, gas phase reactions, heterogeneous reactions, ozone depletion potential
Kinetics of NO formation in combustion: Thermal and prompt mechanism, reactions of NCN radical, partial equilibria at high temperatures, environmental aspects

Vacuum Course

Low and Medium Vacuum: Vacuum definition, pressure ranges and related quantities (particle number density, mean free path, etc.), properties (e.g. flow behaviour); pressure units and conversion; vacuum pumps for generation of low and medium vacuum (rotary vane pump, diaphragm pump, roots pump, liquid ring pump, etc.); low and medium vacuum measurement (hydrostatic gauges, aneroid gauges, pirani gauge, capacitive pressure sensors, etc.).
High and Ultra-High Vacuum: Generation (turbomolecular pump, diffusion pump, cryo pump, ion pump, etc.), high and ultra-high vacuum measurement (e.g. ionization gauges), limitations in vacuum generation, vacuum chambers (materials, surface treatments, etc.), examples of applications that require high and ultra-high vacuum
Basics of Mass Spectrometry: Ionization techniques (electron ionization, chemical ionization, field ionization, electrospray ionization, photoionization, matrix-assisted laser desorption ionization, fast atom bombardment, etc.), mass filters (sector field, quadrupole, time-of-flight), detectors; example mass spectra: terms, interpretation, fragmentation, isotopes
High Resolution Mass Spectrometry: Definitions: Mass resolution, mass resolving power, mass accuracy; factors limiting the resolution of “conventional” mass spectrometry; techniques to improve TOF-MS; Fourier transformation based techniques (FTICR, orbitrap), examples of applications that require high mass resolution
Nanoscopic Methods: Scanning electron microscopy, scanning tunneling microscopy, atomic force microscopy, stimulated emission depletion microscopy; application examples
Diffraction Methods: X-ray structure analysis, Bragg’s law, Ewald’s sphere, Laue and Debye-Scherrer methods, neutron and electron diffraction, low energy electron diffraction (LEED), reflection high-energy electron diffraction (RHEED); application examples
Spectroscopic Methods in Surface Science: Auger electron spectroscopy, UV and X-ray photoelectron spectroscopy; application examples
Temperature Programmed Desorption: Molecule-surface interactions; operation principle of TPD, experimental implementation, data evaluation, interpretation of results; application examples

Looking beyond ...

Data Analysis: Measurement uncertainty, types of uncertainty, (co-)variance, accuracy, precision; Least squares method, regression, signal processing, Fourier transformation
Quantities, Units and Symbols: Quantities, units and symbols in physical chemistry. SI base quantities, realization, NIST, PTB. New developments (kg, K, mol, A)
Sensors: Pressure, temperature, mass flow, oxygen (lambda sensor), ion selective electrodes, light (uv/vis, ir), particles (smoke). Wheatestone bridge circuit, lock-in amplifier.
Rules of Good Scientific Practice: Recommendations of the DFG and rules of the University of Göttingen. Examples of scientific fraud and misconduct.
LaTeX: Text formatting software for the sciences.