Vibrational anharmonicity of the C-H out-of-plane vibrations in some hofmann-type clathrates

Abstract

In our previous reports [1,2], we have discussed the host-guest interactions in Hofmann-type clathrates. The motion of the guest (benzene) molecule has been studied through the changes of the frequencies and the shapes of the bands due to CH out-of-plane vibrations. It was found that one of these bands (the one at around 985 cm −1), splits at LNT, the splitting being dependent on the volume of the tetragonal unit cell. From the recorded FT-IR and Raman spectra of these clathrates, we have made an attempt to calculate some of the anharmonicity coefficients, X ij, for the C-H out-of-plane bending vibrations in Ni(NH 3) 2Ni(CN) 4·2C 6H 6 and Cd(NH 3) 2Ni(CN) 4·2C 6H 6 Hofmann type clathrates. The interaction of the guest (benzene) molecules in these two lattices has been discussed in terms of the calculated anharmonicity constants and the data were compared with the available data for liquid benzene.