Absorption Spectrum of Rubidium in the Presence of Isomeric Hydrocarbons

Absorption spectra of Rb in the presence of various hydrocarbons (ethylene, propylene, butene-1, isobutylene, isobutane, n-pentane, isopentane, neopentane, n-hexane, 3-methylpentane, 2,3-dimethylbutane, and neohexane) were studied for the purpose of determining the dependence of the collision-induced satellite bands on the structure of colliding particles. It was found that the positions of the low-temperature red bands are regularly affected by the differences in structure of the hydrocarbon molecules. In particular, the least branched (straight chain) isomeric molecules produce bands with the smallest band-line separations, and the most branched molecules with four or three methyl groups attached to the same carbon atom produce bands with the largest band-line separations. On the other hand, the positions of the high-temperature red bands as well as the positions of the violet bands are not noticeably affected by the differences in molecular structure of the hydrocarbon isomers employed in this work.