Infrared spectroscopy deuterium substitution

The members of this group of shallow acceptors share a similar structure. They consist of a substitutional impurity binding one hydrogen or deuterium atom in its vicinity. Extensive far infrared spectroscopy studies... 

Certain difficulties arise when using water as a solvent in infrared spectroscopy. The infrared modes of water are very intense and may overlap with the sample modes of interest. This problem may be overcome by substituting water with deuterium oxide (D2O), The infrared modes of D2O occur at different frequencies to those observed for water because of the mass dependence of the vibrational frequency. Table 3.2b lists the characteristic bands observed for both H2O and D2O. 

The pyrrole is separated using a separating funnel and poured into another round-bottomed flask and step 1 is repeated. This procedure is then repeated five times whereupon pyrrole should contain about 98% deuterium. The substitution level is checked by infrared (IR) spectroscopy. Finally, the pyrrole is dried with CaCl2 and then distilled at reduced pressure from CaH2 (in a small-scale vacuum distillation apparatus). 

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