The module explains how detailed information about structure, stereochemistry, and the behaviour of chemical species in solution and in the solid state can be obtained by using luminescence spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and diffraction techniques (specifically X-ray diffraction, neutron diffraction and electron diffraction, as well as electron microscopy). 

Luminescence Spectroscopy  

• Describe the fundamental principles of photoluminescence spectroscopy and the different types of electronically excited states associated with organic molecules and inorganic d- and f-block coordination complexes.       

• Sketch Jablonski energy level diagrams for different classes of compound and apply knowledge of photoexcited state molecules to various applications.   

EPR Spectroscopy 

• Sketch energy level diagrams for electron-nuclear spin systems and predict the appearance of EPR spectra of organic radicals, including the multiplicity of resonance lines.   

• Extract spin Hamiltonian values from experimental spectra and correlate with chemical structure.   

Diffraction Techniques  

• Explain the scope and limitations of X-ray diffraction, neutron diffraction, electron diffraction and electron microscopy techniques in the study of structural properties of solids.   

• Formulate the optimum experimental strategy for exploring specific aspects of solid-state structure.  

21 Lectures, with seven lectures allocated to each of the three components of the module (Luminescence Spectroscopy, EPR Spectroscopy and Diffraction Techniques). Each lecture is held “in person” in a lecture theatre. The duration of each lecture is 50 minutes. Each lecture is recorded, with the recording made available to students on Learning Central on the same day as the lecture.   

Three Formative Workshops, with one formative workshop allocated to each of the three components of the module (Luminescence Spectroscopy, EPR Spectroscopy and Diffraction Techniques). The duration of each formative workshop is 50 minutes. Each formative workshop is held as a whole-class activity in a lecture theatre. Each formative workshop is recorded, with the recording made available to students on Learning Central on the same day as the workshop.   

Interpretation of EPR spectra for paramagnetic species in solution and in the solid state.

Formulating optimum experimental strategies (involving the use of one or more of the X-ray diffraction, neutron diffraction, electron diffraction or electron microscopy techniques) for exploring specific aspects of solid-state structure.

Ability to select appropriate techniques for determination of structure in solution or in the solid state for a range of chemical situations, and to assess the advantages/disadvantages for each particular purpose.

The module is summatively assessed via in course assessments.

There is no examination for this module.

The module is sub-divided into the following three components, which have essentially equal weight:

Luminescence Spectroscopy

Selection rules; quantized description; Jablonski diagrams.

Stokes shift; quantum yield; lifetimes.

Fluorescence; phosphorescence.

Types of chromophores; effect of structure on emission; donor-acceptor.

Energy transfer: Dexter versusFörster.

Quenching pathways: O₂; photoinduced electron transfer.

Applications to coordination complexes: TM; lanthanides.

Chemosensors; imaging; LEDs; PDT.

Chemoluminescence; bioluminescence; electroluminescence.

EPR Spectroscopy

Basic principles of Electron Paramagnetic Resonance (EPR).

Origin and significance of the electron Zeeman and nuclear Zeeman effects.

Derivation of simple spin Hamiltonian for a two spin system (S= ½, I= ½).

Interaction of the electron with its environment – anisotropy and symmetry effects in EPR spectra.

Applications of EPR to characterize paramagnetic systems.

Analysis and interpretation of EPR spectra of organic radicals in solution, as well as main group radicals and transition metal ions in frozen solution.

Interpretation of spin Hamiltonian parameters gand A(hyperfine) values.

Diffraction Techniques

Fundamentals:

Properties of X-rays.

Properties of electron beams.

Properties of neutron beams.

Production of X-rays and other radiation (conventional sources and synchrotron radiation).

Fundamentals of diffraction by crystalline solids.

Applications, Scope and Limitations of Techniques:

X-Ray diffraction (XRD): applications of X-ray diffraction, single-crystal versuspowder X-ray diffraction, advantages of using synchrotron radiation, limitations of X-ray diffraction.

Neutron diffraction (ND): applications of neutron diffraction, neutron diffraction versusX-ray diffraction.

Electron diffraction and electron microscopy: electron diffraction (ED), transmission electron microscopy (TEM), scanning electron microscopy (SEM), low energy electron diffraction (LEED).