Measurements of dielectric constant and dielectric loss at 0.22, 1.25, 3.22, and 10.00 cm have been made upon benzene, hexafluorobenzene, an equimolar mixture of benzene and hexafluorobenzene, a dilute solution of hexachlorobenzene in benzene, and hexane, dodecane, and octadecane. The very small sizes of the dielectric losses observed in this frequency region, where loss due to the rotational orientation of dipolar molecules of this size should be at or near a maximum, indicates the absence of any appreciable permanent molecular dipole moment. The increase of the loss values with increasing frequency in this region indicates that, as already established for benzene, they form the lowhyphen;frequency tail of a veryhyphen;farhyphen;infrared absorption band for each liquid. The absorption presumably arises from the small temporary dipole moments induced by molecular collisions. It is found that the absorption coefficients are increased by the presence of mutually opposing and compensating permanent dipoles and of pgr; electrons in the molecules.
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