This thesis describes the use of density functional theory (DFT) to assist the interpretation
of advanced spectroscopic techniques such as stopped flow Fourier transform infrared
spectroscopy (FTIR), muon spin resonance (�SR), and nuclear inelastic scattering (NIS).
These complementary techniques are used to investigate the structure and mechanism of
a variety of important chemical systems, some of which are relevant to biological energy
transduction and energy harvesting.
The mechanisms by which [FeFe] and [NiFe] hydrogenase enzymes catalyse the reversible
reduction of protons to dihydrogen are of intrinsic interest in the context of a
developing hydrogen technology for energy transduction. Gas phase DFT calculations
are used to simulate and assign structure to experimental solution phase FTIR spectra
for a family of [FeFe]-hydrogenase model complexes. Further, the Mulliken charge distribution
across the Fe centres are compared for di�erent dithiolate bridge groups and
PMe3 ligand positions. In the pursuit of understanding the protonation mechanism of
[FeFe]-hydrogenases, transition state theory is used and the energetics of reaction pathways
leading to terminal and bridging hydrides calculated and compared.
NIS demonstrates great potential for characterising the [FeFe]-hydrogenase mimics.
In order to further develop and validate the technique, a combination of NIS, DFT calculations,
FTIR and Raman spectroscopies are applied to a small Fe(III) model system
in order to provide complete a characterisation of the low frequency meta
