Ultrafast phenomena

Mohrschladt R, Schroeder J, Troe J, Vdhringer P and Votsmeier M 1994 Solvent influence on barrier crossing in the S. -state of c/s- and trans- st ff stiibene Ultrafast Phenomena /Xed P F Barbara et al (New York Springer) pp 499-503... 

Shank C V 1986 Investigation of ultrafast phenomena in the femtosecond domain Science 233 1276-80... 

Passino S A, Nagasawa Y, Joo T and Fleming G R 1996 Photon echo measurements in liquids using pulses longer than the electronic dephasing time Ultrafast Phenomena X ed P Barbara, W Knox, WZinth and J Fujimoto (Berlin Springer) pp 199-200... 

Nelson K A 1994 Coherent control optics, molecules, and materials Ultrafast Phenomena /X ed P F Barbara, W H Knox, G A Mourou and A H Zewail (Berlin Springer) pp 47... 

Jureller, J. E., Scherer, N. F., Birks, T. A., Wadsworth, W. J. and Russell, P. S. J. (2003). Widely tunable femtosecond pulses from a tapered fiber for ultrafast microscopy and multiphoton applications. In Ultrafast Phenomena xiii (Miller, R. J. D., ed.). Springer, Berlin, pp. 684-6. 

From the above discussion, we can see that the purpose of this paper is to present a microscopic model that can analyze the absorption spectra, describe internal conversion, photoinduced ET, and energy transfer in the ps and sub-ps range, and construct the fs time-resolved profiles or spectra, as well as other fs time-resolved experiments. We shall show that in the sub-ps range, the system is best described by the Hamiltonian with various electronic interactions, because when the timescale is ultrashort, all the rate constants lose their meaning. Needless to say, the microscopic approach presented in this paper can be used for other ultrafast phenomena of complicated systems. In particular, we will show how one can prepare a vibronic model based on the adiabatic approximation and show how the spectroscopic properties are mapped onto the resulting model Hamiltonian. We will also show how the resulting model Hamiltonian can be used, with time-resolved spectroscopic data, to obtain internal... 

From the above discussion, we can see that vibrational relaxation plays a very important role in ultrafast phenomena. In this appendix we shall present a model that can describe vibrational relaxation and dephasing (especially pure dephasing). Suppose that... 

Recent developments in laser technology and fast detection methods now allow the kinetic behaviour of the excited state species arising from absorption of radiation by polymers to be studied on time-scales down to the picosecond region ( ). An example of a time-resolved fluorescence spectrometer which can be used to study such ultrafast phenomena is illustrated in Figure 5 Q). 

Various ultrafast phenomena occuring in the femtosecond time-scale in the condensed phase have been studied by fluorescence up-conversion (for a review, see Mialocq and Gustavsson, 2001). As already mentioned in Chapter 7 (Box 7.1),... 

When the optical length of the sample is much shorter than the other factors such as the length of the electron pulse, the response function takes on a Gaussian shape. As the optical length increases, the shape of the response function becomes trapezoidal. Furthermore, a thick sample causes the prolongation of the electron pulse by electron scattering, which leads to the degradation of time resolution. Therefore the experiment to observe ultrafast phenomena requires the use of a thin sample. 

B. Burfeindt, S. Ramakrishna, C. Zimmermann, B. Meifiner, Th. Han-nappel, W. Storck, and F. Willig, In Ultrafast Phenomena XI Springer-Verlag Berlin, p. 636 (1998)... 

H Sakaguchi, T Nagamura. In PF Barbara, JG Fujimoto, WH Knox, W Zinth eds. Ultrafast Phenomena. Berlin Springer-Verlag, 1996, pp 62, 209. 

It can be seen from the discussion in later sections that vibrational relaxation in dense media plays a very important role in ultrafast phenomena. The dynamics of vibrational relaxation can be described as follows. Let Q be the normal coordinate of the system mode and assume that the system oscillator is linearly coupled to the heat bath [8,11-16], i.e.,... 

The RC is an ideal system to test theoretical ideas (memory effect, coherence effect, etc.), fundamental approximations (isolated line approximation, Markov approximation, etc.), and techniques (generalized linear response theory, Forster-Dexter theory, Marcus theory, etc.) for treating ultrafast phenomena. As mentioned above, this ideality is mainly due to the fact that the electronic energy level spacing in RC is small (typically from 200 to 1500 cm-1), and the interactions between these electronic states are weak. 

If quantum chemistry methods cannot be practical to calculate the molecular parameters as potential surfaces of the system, how can one analyze ultrafast phenomena Is it important to identify the electronic... 

Ultrafast Phenomena XVI Proceedings of the 16th International Conference, Palazzo dei Congressi Stresa, Italy,... 

Ultrafast Phenomena XIII Editors D. Miller, M.M. Murnane, N.R. Scherer, and A.M. Weiner... 

Graener H, Dohlus R, Laubereau A. In Fleming GR, Siegman AE, eds. Ultrafast Phenomena V. Berlin Springer, 1986. 

Elsaesser T, Fujimoto JG, Wiersma DA, Zinth W, eds. Ultrafast Phenomena XI. Berlin Springer-Verlag, 1998. 

Hamm P, Wiemann S, Zurek M, Zinth W. A dual-beam sub-picosecond spectrometer for the 5-11 pm spectral region and its application to vibrational relaxation in the Sj state. In Barbara PF, Knox WH, Mourou GA, Zewail AH, eds. Ultrafast Phenomena IX. Berlin Springer-Verlag, 1994 152-153. 

Chudoba C, Nibbering ETJ, Elsaesser T. Dynamics of site-specific excited-state solute-solvent interactions as probed by femtosecond vibrational spectroscopy. In Elsaesser T, Fujimoto JG, Wiersma DA, Zinth W, eds. Ultrafast Phenomena XI. Berlin Springer-Verlag, 1998 535-537. 

Lim M, Jackson TA, Anfinrud PA. Springer Series in Chemical Physics (Ultrafast Phenomena VIII) 55 522-524, 1992. 

Hochstrasser RM, Anfinrud PA, Diller R, Han C, Iannone M, Lian T, Locke B. Femtosecond Infrared Spectroscopy of complex molecules using cw IR lasers. In Harris CB, Ippen EP, Mourou GA, Zewail AH, eds. Ultrafast Phenomena VH. Berlin Springer-Verlag, 1990 429-433. 

Yu J, Fourkas JT, Berg M. Transient hole burning studies of electronic state solvation phonon and structural contributions. In Martin J-L, Migus A, Mourou G, Zewail AH, eds. Ultrafast Phenomena VIII. Berlin Springer-Verlag, 1992. 

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