where T is chosen such that the R (1) (t) is sufficiently decay to zero. For Fig. , for all N , the response signal was simulated up to T = 2.5 ps, where R (1) (t) → 0. In Fig. , all response signals were simulated till T = 800 fs. In Fig. , the response signal for each energy disorder (Eq. 74) decay to 0 with different T . For no disorder case, σ ε = 0.0 eV, we chose T = 1.5 ps. For σ ε = 0.03 eV, 0.04 eV, 0.05 eV, 0.1 eV and 0.2 eV, we chose T = 1 ps, T = 500 fs, T = 300 fs, T = 80 fs and T = 50 fs, respectively. To simulate dipole disorder (Eq. 75), we set T = 1.5 ps for all σ θ cases in Fig. .