Temperature dependence of low-frequency responses of liquid 1-alkenes studied by femtosecond optical Kerr effect spectroscopy

Abstract

Femtosecond time-resolved optical Kerr effect measurements have been performed in three 1-alkene liquids in order to investigate the low-frequency responses in a wide range of temperature, 50 ∼ 290 K, 133 ∼ 290 K and 153 ∼ 290 K for 1-pentene, 1-hexene and 1-heptene, respectively. It has been found that the low-frequency responses of three liquids have two frequency regions where the spectral low-frequency show strong temperature dependence. One is the low frequency part less than several 10 cm −1, which includes the relaxational mode in a very low frequency range. The other is the intramolecular Raman band around 100 cm −1. The origin of the temperature dependence is discussed with the model which consists of anharmonically coupled oscillators.