The vibrational analysis of 1,1-dimethylcyclopropane and 1,1-dimethyl-d6-cyclopropane

The i.r. and Raman spectra of 1,1-dimethylcyclopropane and 1,1-dimethyl-d₆-Cyclopropane have been investigated from 100 to 4000 cm⁻¹. Infrared spectra are reported in the solid and vapor states and Raman spectra are reported for all three physical states. Data from the normal and deuterated samples were used for Teller—Redlich product rule calculations as a check on correctness of the vibrational assignments. The 1 ← 0 and 2 ← 0 torsional transitions were observed and the calculated barriers to internal rotation for the solid and vapor states are 3.7 and 3.2 kcal/mole respectively.