Vv. Eremenko et al., PECULIARITIES OF EXCITON AND EXCITON-MAGNON SCATTERING AND RAMAN-SCATTERING OF LIGHT BY QUASI-2-DIMENSIONAL ANTIFERROMAGNET NH3(CH2)2NH3MNCL4, UKRAINSKII FIZICHESKII ZHURNAL, 37(12), 1992, pp. 1806-1811
The low-temperature studies of Raman scattering and light absorption s
pectra of the quasi-two-dimensional antiferromagnet NH3(CH2)2NH3MnCl4
have been carried out. In both spectra peculiarities which deviate fro
m the framework of assumed before two-sublattice model were found. The
peculiarities are related with distortions which result in doubling o
r the crystal lattice period. The analysis of exciton and exciton-magn
on absorption bands polarization properties makes it possible to give
concrete expression for the nature of these distortions and to make a
conclusion about the absence of the symmetry centre in the Mn2+ magnet
ic ion position.