Fig. 3. 2D-IR spectra of l-P2+˙ (a) and c-P6·T6+˙ (b) at 500 fs delay in the fingerprint region. Black solid and blue dashed contour lines correspond to positive (ESA) and negative (GSB) signals, respectively. Contours near zero are hidden for clarity. Spectra were recorded using a broadband pump centered at ∼1325 cm⁻¹ (FWHM ∼150 cm⁻¹). Optical densities of all samples were ∼0.2–0.4 in the fingerprint region. Linear FTIR spectra are shown in gray along each axis.