  Photoelectron circular dichroism (PECD) is a highly sensitive enantiospecific
spectroscopy for studying chiral molecules in the gas phase using either
single-photon ionization or multiphoton ionization. In the short pulse limit
investigated with femtosecond lasers, resonance-enhanced multiphoton ionization
(REMPI) is rather instantaneous and typically occurs simultaneously via more
than one vibrational or electronic intermediate state due to limited frequency
resolution. In contrast, vibrational resolution in the REMPI spectrum can be
achieved using nanosecond lasers. In this work, we follow the high-resolution
approach using a tunable narrow-band nanosecond laser to measure REMPI-PECD
through distinct vibrational levels in the intermediate 3s and 3p Rydberg
states of fenchone. We observe the PECD to be essentially independent of the
vibrational level. This behaviour of the chiral sensitivity may pave the way
for enantiomer specific molecular identification in multi-component mixtures:
one can specifically excite a sharp, vibrationally resolved transition of a
distinct molecule to distinguish different chiral species in mixtures.
