Zeolite-like molecular sieves are characterized by a regularly arrange
d micropore system. These pores can order adsorbed molecules. The resu
lting guest-host composites are promising materials for spectroscopy b
ecause of the non-random orientation of the transition matrix elements
. By studying the Raman scattering of p-nitroaniline (PNA) within a la
rge aluminophosphate AlPO4-5 crystal, it was found that the PNA molecu
les are very well aligned inside the pores, forming dipole chains with
intermolecular interactions as in the solid.