LINEWIDTHS OF ROTATIONAL SPECTRA OF SYMMETRIC-TOP MOLECULES

Measurements of linewidths are reported for some 50 rotational transitions (J→J+1) of the CHs^Cl, CH337Cl, CH3 79Br, CH381Br, CH3I, CH 3CH, and CH3CCH molecules. The CH3CN molecule has exceptionally wide lines (100 Me/sec·torr) due to the large dipole moment (3.92 D). The experimental data are compared with the theoretical widths which are calculated using the Anderson theory with dipole-dipole interaction. With the exception of the CH3CCH molecule, the theoretical widths are larger than the experimental ones. The over-all agreement between theory and experiment is within 30%.