Figure 3
TR-2PPE spectra.
(a) TR-2PPE spectra (hν = 4.33 eV) at various Δts. Horizontal axis stands for the intermediate energy defined as Efinal−1 hν. (b) Intensity trace of LUMO + 1 against Δt, where the intensity is obtained from an integration of 0.1 eV width around EF + 1.8 eV marked in a. The trace is fitted by a convolution of Gaussian autocorrelation (116 fs in FWHM) and single exponential decay functions. The autocorrelation function was determined in advance from the intensity trace of TR-2PPE for bare HOPG at around EF + 1.5 eV (grey circle). (c) Intensity trace for LUMO. Fitted components of the first (Autocorrelation) and second terms (rise and decay) in eq. (1) are also overwritten as solid lines. Inset shows a wider Δt region (±1 ps).
