Zero-Point Energies of CH2DOH in
the α-Phase for the Three Rotamers

Infrared absorption measurements were made for CH2DOH in the α-phase. The absorption bands of C–D stretching modes of –CH2D were observed at different frequencies depending on the orientation of –CH2D. The considerably large difference in frequency νvib indicated that the zero-point energy Ezero,vib = hνvib/2 was also dependent on the –CH2D orientation. The energy scheme of three levels obtained from the heat capacity was explained by the sum of those contributions in the zero-point energy from all intramolecular vibrations. Normal mode analysis of the single molecule of CH2DOH by DFT calculation supported this interpretation.

(by H. Suzuki & A. Inaba)

Fig. 1. Temperature evolution of the IR spectra obtained for CH2DOH in the spectral range 2100 – 2300 cm-1.

Table 1. Frequencies of normal vibrations and zero-point energies of CH2DOH calculated by DFT method for a single molecule.