Vibrational Relaxation in Doped and Pure Molecular Crystals A Picosecond Photon Echo and CARS Study
Using picosecond photon echoes a detailed study has been made of vibrational relaxation in the system pentacene in naphthalene at 1.5 K. The results indicate that low-frequency modes relax directly through phonon emission, while higher frequency modes decay through vibrational cascading. The role of the medium on the anharmonic intra-molecular vibration-vibration coupling is emphasized.
Delayed picosecond CARS experiments have been used to study relaxation of Frenkel-type vibrational excitons in pure naphthalene. The Raman line- shapes of these excitons are found to be Lorentzian and evidence is presented that this is caused by vibrational exchange narrowing.
KeywordsVibrational Relaxation Phonon Emission Frenkel Exciton Exchange Narrowing Phase Relaxation Time
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- 1.F. Legay in Chemioal and Biochemical Applications of Lasers (Academic Press, New York 1977) edited by C.B. Moore, Vol. II.Google Scholar
- 3.W.H. Hesselink and D.A. Wiersma in Ficosecond Phenomena edited by C.V. Shank, E.P. Ippen and S.L. Shapiro, pg. 192 (Springer-Verlag, Berlin, 1978).Google Scholar
- 4.W.H. Hesselink and D.A. Wiersma, J. Chem. Phys., July 15th issue, 1980.Google Scholar
- 5.W.H. Hesselink and D.A. Wiersma, Phys. Rev. Letters 43, (1979) 1991.Google Scholar
- 9.A. van der Ende and R.P.H. Rettschnick, Proc. “Ultrafast Phenomena in Spectroscopy”, Tallinnxx 1978.Google Scholar
- A. Amirav Chem. Phys. Letters 71 (1980) 12; ibid. 72 (1980) 21.Google Scholar