Summary of crystal field spectra

Al-sites in micas, zoisite, corundum hydrated cation  

5 Crystal field spectra of transition metal ions 

Assembled in table 5.11 are the crystal field parameters derived from the spectra of several Cr3+-bearing minerals. For non-cubic minerals, the energies of bands and t)2 represent values averaged from the polarized absorption spectra. Crystal field stabilization energies calculated from band Dj, and corresponding to 1.2 x A0 (table 2.2), decrease in the order 

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The lattice vibrations of molecular solids have received brief consideration in reviews dealing with the infrared spectra of these solids (Dows, 1963,1965, 1966). ThereviewbySchnepp (1969) provides a good summary of the field. A recent review by Venkataraman and Sahni (1970) of the lattice dynamics of complex crystals contains much subject matter related to the present review. A number of good reviews are available on the lattice motions of ionic, covalent, and metallic solids (Mitra and Gielisse, 1964 Martin, 1965 Cochran and Cowley, 1969). 

In 1958, spinning of a NaCl crystal at a 90° angle with the magnetic field is achieved [6]. Later, MAS was implemented at a 7000 Hz rate and Fourier transformed NMR spectra of Teflon and CaF2 were recorded in 7 mm rotors [7]. In 1997, 2.5 mm rotors (for MAS rates up to 33-35 kHz) became commercially available by Bruker. Samoson and the group in Tallinn realized numerous technology-driven developments MAS rates of 50 kHz with rotors of 2 mm diameter were demonstrated in 1999 in their laboratory [8]. Nowadays, very fast (>30 kHz) and ultrafast (>40—50 kHz) MAS probes are now commercially available (see Fig. 3.2 for a summary), with the commercial release by JEOL of a 110 kHz MAS probe with a 0.75 mm rotor announced in 2012 at the 53rd ENC Conference. 

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