Terahertz reflection time domain spectroscopy of branched alkanes

The temperature dependent spectroscopic properties of 2-methylpentadecane were measured over several path lengths using terahertz reflection time-domain spectroscopy. The variation of the index of refraction and absorption with temperature was consistent with the behavior of the linear chain n-alkanes in previous studies. However, an increased absorption coefficient was observed indicating a larger induced dipole moment compared to its structural isomers, the higher symmetry n-hexadecane and the highly branched alkane 2,2,4,4,6,8,8-heptamethylnonane.