A study of (R)-3-methylcyclopentanone [(R)-3-MCP] by photoelectron
spectroscopy and photoelectron circular dichroism
(PECD) is presented. The synchrotron radiation gas-phase photoelectron
spectra of (R)-3-MCP were measured and are discussed
on the basis of different theoretical methodologies. The
experimental dichroism of (R)-3-MCP for selected deconvoluted
valence states and for the carbonyl carbon 1s core state are reported
and reproduced well by calculated dispersions generated
by considering the contributions of two different conformers.
The theoretical dichroic parameters are calculated by employing
a multicentre basis set of B-spline functions and
a Kohn–Sham Hamiltonian. Temperature-dependent PECD
studies of the HOMO state and the carbonyl carbon 1s core
level allowed the separation of the contributions of each conformer
by photoelectron dichroism. This new approach clearly
shows how the PECD methodology is sensitive to conformational
and structural changes of unoriented (R)-3-MCP in the
gas phase, opening up new perspectives in the characterisation
of chiral molecular systems.
