Crystal structure prediction lattice vibrations

While the examples in Scheme 7.16 hinted at the practicality of the solid state photodecarbonylation of ketones, the factors controlling this reaction remained unknown until very recently. As a starting point to understand and predict the photochemical behavior of ketones in terms of their molecular structures, we recall that most of the thermal (kinetic) energy of crystals is in the form of lattice vibrations. 

Fundamentals. The band origins of the symmetric stretch Vi at 3121.9306 0.0061 cm and of the antisymmetric stretch V3 at 3190.291 0.014 cm" were identified for gaseous NHJ in a high-resolution IR spectrum. Differences between the fundamentals of NH2 in different salts are attributable to matrix effects in the crystal lattice [2]. The bending vibration V2 = 1462 20 cm was predicted for gaseous NH from the CEPA equilibrium structure... 

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