Loop diagram, describing the strong pulse pump interaction followed by a weak probe pulse. For details see text.
Pulse envelope, total vibrational energy, and vibrational population P ν(t) in the CO-stretch in carboxy-hemeoglobine for a typical set of parameters: τ0 = 100 fs, ω0 = 1980.0 cm−1, ϕ″ = −0.1 ps2, and a peak power .
Energy transfer achieved by linearly chirped laser pulses as a function of detuning form the center of the absorption band Δω0 and the chirp parameter ϕ″ with a pulse duration of τ0 = 100 fs (a)–(d) and τ0 = 300 fs (e)–(h), and a peak power of (a), (b), (e), and (f) and (c), (d), (g), and (h).
Optimal detuning δopt of the excitation laser with respect to the center of the absorption band, required to obtain maximum vibrational energy transfer as a function of the peak power. The chirp parameter is set to ϕ′′ = −0.1ps2 (full lines), and compared to an unchirped (Fourier-transform limited) (dashed lines).
Effect of chirp parameter ϕ″ and fluctuations onto vibrational excitation of HbCO. Optimal detunings for ϕ′′ = −0.1ps2 were used and a peak power of .
Distribution of vibrational populations after strong IR pulse excitation, using different pulse lengths including or suppressing protein fluctuations. The other pulse parameters are ϕ′′ = −0.1 ps2, , and the corresponding optimal detunings.
(Red) Distribution of vibrational populations after strong IR pulse interaction, for different pulse lengths and chirp parameters. Optimal detunings for ϕ′′ = −0.1 ps2 were used and a peak power of . (Blue) As above, but the vibrational populations are calculated by weighting the individual wavepackets by the projection onto the laser polarization axis.
Differential transient absorption spectra (see Eq. (24) ) for different pulse lengths and chirp parameters, as indicated. Optimal detunings for ϕ′′ = −0.1ps2 were used and a peak power of .
(Top panel) Simulated differential transient absorption signal , using different pulse intensities, based on an orientational averaging and averaging over the spatial beam profile (Eq. (25) ). A pulse duration of τ = 100 fs, a detuning of Δω = −61.7 cm−1, and a chirp parameter ϕ′′ = −3.2 × 10−2ps2 were used. (Bottom panel) Experimental spectra, taken from Ref. 23 and based on the same set of parameters.
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