Fig. 3. Fourier transform of the time-dependent dipole moment of Cd₃₈Se₃₈-ZnPc-32(NH₂CH₃).

a Dipole spectrum obtained from the small matrix approximation (SMA) with the corresponding time-dependent dipole signal (Dip.). b Selected narrow features from the SMA calculation. c Narrow feature position after optimization. The error with respect to exact short-time dynamics is notably reduced. d The full time-dependent signal is now reproduced with high accuracy and all features are correctly reproduced in the spectrum. The SMA signal in (a) and (b) was scaled to match the maximum amplitude of the time-dependent density functional theory (RT-TDDFT) reference within the given time window. This is only done for a better comparison of the signal wave forms. For the sake of simplicity and without loss of generality, we only show the dipole moment in x-direction after an electric field pulse in the same direction. Int. is the abbreviation for intensity.