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The infrared (vapor, and solid at 15°K) and Raman (vapor and liquid) spectra in the region of 2700–3200 cm−1 are reported for three deuterated analogs of trimethylene oxide, viz. α-d2, β-d2, and α,α′-d4, and compared to the spectra of the normal compound. All principal infrared absorptions and Raman lines have been identified and assigned to vibrational modes of the α-CH2 and β-CH2 groups (six stretching fundamentals and three scissoring overtones). A number of band sequences are observed in the infrared and Raman spectra of the vapors. They are ascribed to combinations of various C–H stretching fundamentals and CH2 scissoring overtones with the ring puckering vibration and its overtones. The puckering separations in these vibrationally excited states in general do not differ greatly from the pure puckering differences.

Band progressions have been observed in the CH, scissoring region of the i.r. spectra of trimethylene oxide (C,H,O) and three of its deuterated analogs (a-d,, 8-d,, and a,a'-d,). With the aid of the pure ring puckering transitions (published previously) and a simple theoretical model of puckering-vibrational interactions the absorptions have been assigned to combination tones of CH, scissoring vibrations with the ring puckering mode and its overtones. The scissoring fundamentals of the a-and 8-methylene groups have been identified and assigned. Of all the vibrations for which combination progressions are observed, only the P-CH, scissoring mode of the normal compound exhibits significant differences between the ring puckering transitions in the ground state and the vibrational excited state.Nous avons observe les progressions de bande dans la region de cisaillement du CH, du spectre i.r.