Measurement of Nuclear Spin Conversion Rates in Molecules

As for the determination of precise energy levels and the torsional potential barrier, we have obtained the following results. In references (3) and (5), we experimentally determined torsion-rotation energy levels with a high precision. Theoretically, torsion-rotation Hamiltonian with new higher order terms was developed and applied to determine energy levels for CH_3^<18>OH in reference (1).Theory to calculate centrifugal distortion constants was developed for methanol in reference (2). Centrifugal distortion constants for CH_3OH and CD_3OH including isotopic species have been calculated in references (4) and (6), respectively.