Temperature-dependent (10-240 K) relaxation of vibrational excitons in KClO4 crystal
Anno: 1989
Autori: Righini R., Angeloni L., Foggi P., Castellucci E., Califano S.
Affiliazione autori: Dipartimento di Chimica, Università di Firenze, 50121 Florence, Italy
Abstract: The relaxation times of vibrational excitons in KClO4 have been measured between 10 and 240 K by picosecond time-resolved CARS spectroscopy. The low temperature data are consistent with energy decay mechanisms based on three-phonon scattering processes. At higher temperature the linewidth of the symmetric stretching ?1 has a well defined linear dependence on T, showing that three-phonon scattering is still the main relaxation mechanism. In contrast, the ?2 bending mode has a marked T2 dependence, showing that four-phonon and higher-order depopulation and dephasing mechanisms control the overall relaxation rate. Finally, the strong temperature dependence of the linewidth of the 2?2 overtone is interpreted in terms of the relaxation of an undispersed, quasi-free two-phonon state.
Giornale/Rivista: CHEMICAL PHYSICS
Volume: 131 (2-3) Da Pagina: 463 A: 472
Parole chiavi: potassium perchlorateDOI: 10.1016/0301-0104(89)80191-0Citazioni: 17dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-04-28Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui