Fourier components dimers

Fig. 2. (a,b) Transient absorption on the v0h=1— 2 transition of OH/OH dimers (symbols). The spectrally integrated, anisotropy free absorption change AA is plotted as a function of the delay time between the pump centered at Ep=2950 cm 1 and the probe centered at Epr. Solid lines exponential decay with a time constant of 200 fs. Inset of Fig. (b) Fourier transform of the oscillatory component of the transient in Fig. (b) displaying an oscillation frequency of 145 cm 1. 

Fig. 3. (a-c) Time resolved changes of the O-H stretching absorption of OH/OH dimers as measured with spectrally integrated probe pulses centered at Epr and corrected for rotational diffusion (symbols, pump pulses centered at Ep=2950 cm"1). The solid lines represent numerical fits based on exponential kinetic components with time constants of 200 fs, 1 ps and 15 ps. Inset of Fig. (c) Time evolution up to a 70 ps delay time, (d-f) Oscillatory component of the signals in Figs, (a-c) and Fourier transforms (insets). 

Fig. 4. (a) Time resolved changes of O-H stretching absorption in OH/OH (solid symbols) and OH/OD dimers (open circles) measured with parallel polarization of pump and probe and spectrally resolved detection of the probe at 2880 cm 1. Solid lines Calculated decay with time constants of 1 and 15 ps. (b) Oscillatory signal components from OH/OH (solid line) and OH/OD dimers (dotted line). The Fourier transforms shown in the inset display a major frequency component at 145 cm 1 in both cases. 

Such features of a beatnote demonstrate the presence of more than one oscillation frequency. In Fig. 15.6 (a), the Fourier transforms of the oscillatory signals are plotted for the 3 spectral positions. There are 3 prominent frequency components, a strong doublet with maxima at 145 and 170 cm i and a much weaker component around 50 cm h Comparative pump-probe studies of OH/OH dimers reveal a similar doublet at 145 and 170 cm i with slightly changed relative intensities of the two components. The 50 cm i component is practically absent in the OH/OH... 

---