Nuclear wavepacket motion

Takeuchi T, Tahara T (2005) Coherent nuclear wavepacket motions in ultrafast excited-state intramolecular proton transfer sub-30-fs resolved pump-probe absorption spectroscopy of 10-hydroxybenzo[h]quinoline in solution. J Phys Chem A 109 10199-10207... 

The approach has been tested by controlling nuclear wavepacket motion in a two-dimensional model system [23], The relative simplicity of the system makes it possible to compare the semiclassical results with exact quantum ones. Numerical applications to the control of HCN-CNH isomerization [24] demonstrates that the new semiclassical formulation of optimal control theory provides an effective and powerful tool for controlling molecular dynamics with many degrees of freedom. 

Yakovlev, A.G., Shkuropatov, A.Y. and Shuvalov, VA. (2000) Nuclear wavepacket motion producing a reversible charge separation in bacterial reaction centers, FEBS Letters 466, 209-212. 

PPE signals give direct information on the density of states of the unoccupied states which is obtained only indirectly with other optical methods. One drawback is that since the excited electrons are detected, the observation time window is limited to the lifetime of the excited electrons. The excited state lifetimes at metal surfaces are typically less than a few hundreds of femtoseconds and much shorter than vibrational relaxation times. Hence the information is limited to that in the very beginning of the nuclear wavepacket motion, right after the photoexcitation. 

Nuclear Wavepacket Motions of Adsorbate Probed by Time-Resolved 2PPE 343... 

Nuclear Wavepacket Motion at Surfaces Probed by Time-Resolved SHG 345... 

Figure 19.3 shows typical traces of time-resolved SHG from alkali-covered Pt(lll). In both cases, clear oscillatory components appear and they are ascribed to nuclear wavepacket motion of surface modes. There exist more than two components, which becomes clear by Fourier transforming the time-domain data (Figure 19.4). The Fourier spectra are obtained from the raw data with a delay time larger than 50 fs by subtracting background components whose frequencies are less than ITHz. For Cs adsorbate, a peak at 2.3 THz is prominent and is due to the Cs—Pt stretching mode, while the corresponding stretching mode is observed at 4.8 THz for K adsorbate.

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