  Enantioselective interactions of chiral molecules include distinct
absorptions to opposite-handed circularly polarized light, known as chiral
absorption. Traditionally, chiral absorption has been primarily attributed to
electric dipole and magnetic dipole interaction with molecular chirality.
However, this approach falls short for large molecules that support high-order
multipolar components, such as electric quadrupole moment. Here, we introduce a
theoretical model to study the chiral absorption of large molecules in the
presence of plasmonic nanostructures. This model considers both electric
dipole-magnetic dipole interaction and electric dipole-electric quadrupole
interaction enhanced by a resonant structure. We numerically study such
interactions of the chiral molecular solution in the vicinity of a nonchiral
plasmonic nano-resonator. Our results show the distinct spectral information of
the chiral media on- and off-resonance of the resonator.
