  The paper presents main aspects of the Dipole-Quadrupole theory of Surface
Enhanced Infrared Absorption (SEIRA). It is pointed out the possibility of
appearance of the lines, caused by totally symmetric vibrations transforming
after the unit irreducible representation, which are forbidden in usual
infrared absorption spectra in molecules with sufficiently high symmetry.
Observation of such lines in the SEIRA spectra of diprotonated and ethylene,
adsorbed on and on mordenites is pointed out. The results well agree with our
ideas about surface enhanced optical processes, based on the conception of a
strong quadrupole light-molecule interaction, which allows us to develop the
SERS and SEHRS theories.
