Force constant matrix defect

The effeet of eharged niekel ions on the vibration spectrum of ZnO crystals was studied by ealeulating the S5mimetrized LVDS in perfect and defective crystals using a cluster of 1000 ions (region 1). For the calculation of the Coulombic component of the diagonal elements of the force constant matrixes of the ion-ion interactions by the Ewald method about 4000 ions were considered for region 2. 

Let us introduce a CD2 group as a defect in n-alkanes (CH3-(CH>)nCH3) or n-alkyl chain (CH3(CH2)xX or in any polymethylene chain. This is a typical case of mass defect which leaves the force constant matrix (Eq. 3-3)) unchanged because of Born-Oppenheimer approximation. The site where the CD2 group is located can be changed along the chain. Chemically, this can be easily achieved and selectively deuterated n-alkane or alkyl derivatives are either commercially available or can be (and have been) easily synthesized. 

---