Abstract
Absorption spectra of 4 isotopes of methyl alcohol were measured in the far infrared region (15-70 cm-1) using the high-efficiency polarizing interferometer. Absoption cell is 60 cm in length and 5 cm in diameter, in which 5 torr vapor of each specimen (purity 99%) is contained. Each spectrum is analysed in comparison with the theoretical curves. In theory, Hamiltonians by an asymmetry of molecule, rotational distorsion and highr-order potential of internal rotation are taken into account as perturbation. In the lower wave number region, about 30 absorption lines in each spectrum are assigned using 4 kinds of quantum number.
