Temperature-dependent vibrational relaxation in isotopically mixed molecular crystals by picosecond CARS

✍ Scribed by Ta-Chau Chang; Bih-Hwang Jou; Rua-Shin Ou; Chien-Chih Chiang; Hung-Wen Li

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 582 KB
• Volume: 187
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(91)90414-5

✦ Synopsis

Temperature-dependent dephasing of 511, 766 and 1385 cm-' modes in the mixed crystals of naphthalene and perdeuteronaphthalene at various isotopic levels have been studied by picosecond CARS in the region of 6-130 K. In general, adding the isotope shows a significant effect on the low-temperature decay time. However, a small effect on the temperature dependence is observed in the Arrhenius plots of In[Av(T) -Av(6 K)] versus I/Tfor all three modes. This behavior is described by a large change of the thermally activated phonon density of states at low temperature, but by a small change as temperature increases.