Matrix raman spectra, molecular structure and vibrational analysis of SeO2 and (SeO2)2

Matrix Raman data are reported for monomeric SeO2 for the first time. The diffusion controlled polymerisation of the monomer in the matrix, to the dimer and to higher aggregates, is also observed using Raman spectroscopy. Additional evidence for the vibrational and stereochemical assignments for the (SeO2)2 molecule is obtained by normal coordinate calculations for four possible symmetries of the dimer. The data provide convincing evidence that the centrosymmetric chair (C2h) configuration for (SeO2)2 is strongly favoured.