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The micro Raman spectrum of ∼100fg of the clay materials Muscovite and Vermiculite in the region of 600 cm−1 −3300 cm−1 is reported. An attempt has been made to assign the observed Raman shifts in particular those of H‐bonded OH−, which may have significance to an understanding of the role which clay plays in the absorption of soil water.

Can. J . Chem. 61, 14 (1983). We present a modification of a supermolecule model of a general chlorophyll dimer, and calculate the excited state electronic Raman selection rules between the various singlet states. The model utilizes the electronic part of the total wavefunction within the strong intermolecular coupling scheme. Under this condition and the neglect of underlying orbitals, thc electronic wave function of the dimer is reduced to a four orbital function with each monomer contributing one HOMO and one LUMO. Using a Huckel type molecular orbital calculation, the one electron orbital energies and coefficients of the ground and excited state wavefunctions of the dimer are obtained and are shown to depend explicitly on the ground and excited state intermolecular interaction terms. The resulting Raman activity calculation between the various excited state configurations yields two types of tensor elements: ( I ) contains only coordinates of the individual monomer a , (molecule 1) and a? (molecule 2) and are called spatially localized elements and (2) labelled spatially delocalized and contains coordinates of both monomer molecules simultaneously (a3 and a4). [Traduit par le journal]

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