Fig. 5: Density functional theory (DFT) calculations of the vibronic couplings and excited-state infrared (IR) dipoles for pyrene and 1-pyrene acetic acid (PAA). | Nature Communications

Fig. 5: Density functional theory (DFT) calculations of the vibronic couplings and excited-state infrared (IR) dipoles for pyrene and 1-pyrene acetic acid (PAA).

From: Theory predicts UV/vis-to-IR photonic down conversion mediated by excited state vibrational polaritons

Fig. 5

Calculated absorption spectra for (a) pyrene and (b) PAA were performed at different temperatures (red = 300 K; blue = 0.1 K) and with different standard deviations (σ) for the Gaussian distribution of electronic energies taken to represent inhomogeneous broadening (red = 200 cm−1; blue = 10 cm−1). Experimental spectra (black) were taken in cyclohexane for pyrene and toluene for PAA at room temperature (~293 K). Calculated Huang–Rhys factors (S) and excited-state IR dipole moments (\({\mu }_{{{{{{{{\rm{IR}}}}}}}}}^{(e)}\)) for vibrational modes of (c) pyrene and (d) PAA are plotted as a function of the wavenumber of each mode. \({\mu }_{{{{{{{{\rm{IR}}}}}}}}}^{(e)}\) is plotted “on top of” the S values, and are only shown for modes with S > 0, while its value is indicated above each bar.

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